Methods and materials for producing 7-carbon monomers

ABSTRACT

This document describes biochemical pathways for producing 7-aminoheptanoic acid using a β-ketoacyl synthase or a β-ketothiolase to form an N-acetyl-5-amino-3-oxopentanoyl-CoA intermediate. 7-aminoheptanoic acid can be enzymatically converted to pimelic acid, 7-hydroxyheptanoic acid, heptamethylenediamine or 1,7-heptanediol or corresponding salts thereof. This document also describes recombinant microorganisms producing 7-aminoheptanoic acid as well as pimelic acid, 7-hydroxyheptanoic acid, heptamethylenediamine and 1,7-heptanediol or corresponding salts thereof.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 16/380,842, filed Apr. 10, 2019, which is a continuation of U.S. application Ser. No. 16/113,068, filed on Aug. 27, 2018, which is a continuation of U.S. application Ser. No. 15/368,092, filed on Dec. 2, 2016, which claims priority to U.S. Provisional Application No. 62/263,299, filed Dec. 4, 2015, all of which are incorporated herein by reference.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Dec. 29, 2016, is named 12444_0620-00000_SL.txt and is 118,685 bytes in size.

TECHNICAL FIELD

This invention provides methods for biosynthesizing 7-carbon monomers. For example, the present invention provides methods for making N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof using a polypeptide having the activity of a β-ketoacyl synthase or a β-ketothiolase and enzymatically converting N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof to 7-aminoheptanoic acid or a salt thereof using one or more polypeptides having the activity of a 3-hydroxyacyl-CoA dehydrogenase, an enoyl-CoA hydratase, a trans-2-enoyl-CoA reductase, a β-ketothiolase, a thioesterase or a CoA-transferase and a deacetylase or methods using microorganisms expressing one or more of such enzymes. This invention also provides methods for converting 7-aminoheptanoic acid to one or more of pimelic acid, 7-hydroxyheptanoic acid, heptamethylenediamine and 1,7-heptanediol or the corresponding salts thereof using one or more polypeptides having the activity of isolated enzymes such as dehydrogenases, reductases, acetyltransferases, deacetylases, and transaminases or methods using recombinant microorganisms expressing one or more such enzymes.

BACKGROUND

Nylons are synthetic polymers composed of polyamides which are generally synthesized by the condensation polymerization of a diamine with a dicarboxylic acid. Similarly, nylons also may be produced by the condensation polymerization of lactams. Nylon 7 is produced by polymerization of 7-aminoheptanoic acid, whereas Nylon 7,7 is produced by condensation polymerization of pimelic acid and heptamethylenediamine. No economically cost competitive petrochemical route exists to produce the monomers for Nylon 7 and Nylon 7,7.

Given no economically cost competitive petrochemical monomer feedstock, biotechnology offers an alternative approach via biocatalysis. Biocatalysis is the use of biological catalysts, such as enzymes, to perform biochemical transformations of, for example, bioderived feedstocks and petrochemical feedstocks which can both be viable starting materials for the biocatalysis processes.

SUMMARY

Accordingly, against this background, it is clear that there is a need for sustainable methods for producing one or more of 7-aminoheptanoate, pimelic acid, 7-hydroxyheptanoate, heptamethylenediamine, and 1,7-heptanediol or derivatives thereof, wherein the methods are biocatalyst based. This document is based at least in part on the discovery that it is possible to construct biochemical pathways for using, inter alia, a polypeptide having the activity of a β-ketoacyl synthase or a β-ketothiolase to produce 7-aminoheptanoate or a salt thereof, which can be converted in one or more enzymatic steps to pimelic acid, 7-hydroxyheptanoic acid, heptamethylenediamine or 1,7-heptanediol or corresponding salts thereof. Pimelic acid and pimelate, 7-hydroxyheptanoic acid and 7-hydroxyheptanoate, and 7-aminoheptanoic acid and 7-aminoheptanoate are used interchangeably herein to refer to the compound in any of its neutral or ionized forms, including any salt forms thereof. It is understood by those skilled in the art that the specific form will depend on pH.

For compounds containing carboxylic acid groups such as organic monoacids, hydroxyacids, amino acids and dicarboxylic acids, these compounds may be formed or converted to their ionic salt form when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base. Acceptable organic bases include ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like. Acceptable inorganic bases include aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, and the like. The salt can be isolated as is from the system as the salt or converted to the free acid by reducing the pH to below the pKa through addition of acid or treatment with an acidic ion exchange resin.

For compounds containing amine groups such as but not limited to organic amines, amino acids and diamine, these compounds may be formed or converted to their ionic salt form by addition of an acidic proton to the amine to form the ammonium salt, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 2-naphthalenesulfonic acid, 4-methylbicyclo-[2.2.2]oct-2-ene-1-carboxylic acid, glucoheptonic acid, 4,4′-methylenebis-(3-hydroxy-2-ene-1-carboxylic acid), 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid or muconic acid. Acceptable inorganic bases are known in the art and include aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, and the like. The salt can be isolated as is from the system as a salt or converted to the free amine by raising the pH to above the pKb through addition of base or treatment with a basic ion exchange resin.

For compounds containing both amine groups and carboxylic acid groups such as but not limited to amino acids, these compounds may be formed or converted to their ionic salt form by either 1) acid addition salts, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like; or formed with organic acids such as acetic acid, propionic acid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvic acid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, 3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, 1,2-ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 2-naphthalenesulfonic acid, 4-methylbicyclo-[2.2.2]oct-2-ene-1-carboxylic acid, glucoheptonic acid, 4,4′-methylenebis-(3-hydroxy-2-ene-1-carboxylic acid), 3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid, lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoic acid, salicylic acid, stearic acid, muconic acid. Acceptable inorganic bases include aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, and the like or 2) when an acidic proton present in the parent compound either is replaced by a metal ion, e.g., an alkali metal ion, an alkaline earth ion, or an aluminum ion; or coordinates with an organic base. Acceptable organic bases are known in the art and include ethanolamine, diethanolamine, triethanolamine, tromethamine, N-methylglucamine, and the like. Acceptable inorganic bases are known in the art and include aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, and the like. The salt can be isolated as is from the system or converted to the free acid by reducing the pH to below the pKa through addition of acid or treatment with an acidic ion exchange resin.

It has been discovered that appropriate non-natural pathways, feedstocks, microorganisms, attenuation strategies to the microorganism's biochemical network and cultivation strategies may be combined to efficiently produce 7-aminoheptanoate as a C7 (7-carbon) building block, or convert 7-aminoheptanoate to other C7 building blocks such as pimelic acid, 7-hydroxyheptanoic acid, heptamethylenediamine or 1,7-heptanediol or the corresponding salts thereof.

In some embodiments, a terminal carboxyl group can be enzymatically formed using a thioesterase, a CoA transferase, a co-transaminase, an aldehyde dehydrogenase, a 5-oxopentanoate dehydrogenase, a 6-oxohexanoate dehydrogenase or a 7-oxoheptanoate dehydrogenase. See FIG. 2 and FIG. 3.

In some embodiments, a terminal amine group can be enzymatically formed using a carboxylate reductase, a ω-transaminase or a deacylase. See FIG. 4A-E. The co-transaminase can have at least 70% sequence identity to any one of the amino acid sequences set forth in SEQ ID NOs. 7-12. Furthermore, the co-transaminase can have at least 70% sequence identity to any one of the amino acid sequences set forth in SEQ ID NOs. 7-12 and be capable of transferring at least one amine group separated from a carbonyl group by at least one methylene insertion.

In some embodiments, a terminal hydroxyl group can be enzymatically formed using an alcohol dehydrogenase. See FIG. 5 and FIG. 6.

In one aspect, this document features a method of producing N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof. The method includes enzymatically converting β-alanine to N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof via N-acetyl-3-aminopropanoate and N-acetyl-3-aminopropanoyl-CoA. β-alanine is converted to N-acetyl-3-aminopropanoate using a polypeptide having the activity of an acetyl-transferase classified under EC 2.3.1.-. N-acetyl-3-aminopropanoate is converted to N-acetyl-3-aminopropanoyl-CoA using a polypeptide having the activity of a CoA ligase classified under EC 6.2.1.- or a CoA-transferase classified under EC 2.8.3.-.

N-acetyl-3-aminopropanoyl-CoA is converted to N-acetyl-5-amino-3-oxopentanoyl-CoA using a polypeptide having the activity of a β-ketoacyl synthase classified under EC. 2.3.1.- (e.g., EC 2.3.1.180) or a β-ketothiolase classified under EC. 2.3.1.- (e.g., EC 2.3.1.16 or EC 2.3.1.174) The polypeptide having the activity of a β-ketothiolase can have at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO:1 or SEQ ID NO:13. Furthermore, the polypeptide having the activity of a β-ketothiolase can have at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO:1 or SEQ ID NO:13 and be capable of converting N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA. The polypeptide having the activity of a β-ketoacyl synthase can have at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO: 14. Furthermore, the polypeptide having the activity of a β-ketoacyl synthase can have at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO: 14 and be capable of converting N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA.

The method can include enzymatically converting N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof to 7-aminoheptanoate using a plurality of polypeptides having the activities of a 3-hydroxyacyl-CoA dehydrogenase, an enoyl-CoA hydratase, a trans-2-enoyl-CoA reductase, a β-ketothiolase, a thioesterase or a CoA transferase and a deacetylase.

The polypeptide having the activity of a 3-hydroxyacyl-CoA dehydrogenase can be classified under EC 1.1.1.35, EC 1.1.1.36, EC 1.1.1.100 or EC 1.1.1.157. The polypeptide having the activity of an enoyl-CoA hydratase can be classified under EC 4.2.1.17 or EC 4.2.1.119. The polypeptide having the activity of a trans-2-enoyl-CoA reductase can be classified under EC 1.3.1.38, EC 1.3.1.44 or EC 1.3.1.8. The polypeptide having the activity of a β-ketothiolase can be classified under EC 2.3.1.16 or EC 2.3.1.174. The polypeptide having the activity of a thioesterase or CoA transferase can be classified under EC 3.1.2.- or EC 2.8.3.- respectively. The polypeptide having the activity of a deacetylase can be classified under EC 3.5.1.-.

In one aspect, this document features a method for biosynthesizing 7-aminoheptanoate or the salt thereof. The method includes enzymatically converting N-acetyl-3-aminopropanoate to N-acetyl-5-amino-3-oxopentanoyl-CoA via N-acetyl-3-aminopropanoyl-CoA. N-acetyl-3-aminopropanoate is converted to N-acetyl-3-aminopropanoyl-CoA using a polypeptide having the activity of a CoA ligase classified under EC 6.2.1.- or a CoA-transferase classified under EC 2.8.3.-. N-acetyl-3-aminopropanoyl-CoA is converted to N-acetyl-5-amino-3-oxopentanoyl-CoA using a polypeptide having the activity of a β-ketoacyl synthase classified under EC 2.3.1.- (e.g., EC 2.3.1.180) or a β-ketothiolase classified under EC. 2.3.1.- (e.g., EC 2.3.1.16 or EC 2.3.1.174). The β-ketothiolase can have at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO:1 or SEQ ID NO:13. Furthermore, the β-ketothiolase can have at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO:1 or SEQ ID NO:13 and be capable of converting N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA. The β-ketoacyl synthase can have at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO:14. Furthermore, the β-ketoacyl synthase can have at least 70% sequence identity to the amino acid sequence set forth in SEQ ID NO:14 and be capable of converting N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA.

N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof can be converted to N-acetyl-5-amino-3-hydroxypentanoyl-CoA using a polypeptide having the activity of a 3-hydroxyacyl-CoA dehydrogenase. N-acetyl-5-amino-3-hydroxypentanoyl-CoA can be converted to N-acetyl-5-amino-pent-2-enoyl-CoA using a polypeptide having the activity of an enoyl-CoA hydratase. N-acetyl-5-amino-pent-2-enoyl-CoA can be converted to N-acetyl-5-amino-pentanoyl-CoA using a polypeptide having the activity of a trans-2-enoyl-CoA reductase. N-acetyl-5-amino-pentanoyl-CoA can be converted to N-acetyl-7-amino-3-oxoheptanoyl-CoA using a polypeptide having the activity of a β-ketothiolase. N-acetyl-7-amino-3-oxoheptanoyl-CoA can be converted to N-acetyl-7-amino-3-hydroxyheptanoyl-CoA using a polypeptide having the activity of a 3-hydroxyacyl-CoA dehydrogenase. N-acetyl-7-amino-3-hydroxyheptanoyl-CoA can be converted to N-acetyl-7-amino-hept-2-enoyl-CoA using a polypeptide having the activity of an enoyl-CoA hydratase. N-acetyl-7-amino-hept-2-enoyl-CoA can be converted to N-acetyl-7-amino-heptanoyl-CoA using a polypeptide having the activity of a trans-2-enoyl-CoA reductase. N-acetyl-7-aminoheptanoyl-CoA can be converted to N-acetyl-7-amino-heptanoate using a polypeptide having the activity of a thioesterase or a CoA transferase. N-acetyl-7-amino-heptanoate can be converted to 7-aminoheptanoate using a polypeptide having the activity of a deacetylase.

Any of the methods further can include enzymatically converting 7-aminoheptanoate to pimelic acid, 7-hydroxyheptanoate, heptamethylenediamine or 1,7-heptanediol or the corresponding salts thereof in one or more steps.

For example, 7-aminoheptanoate can be enzymatically converted to pimelic acid using one or more polypeptides having the activity of a ω-transaminase, a 7-oxoheptanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, a 5-oxopentanoate dehydrogenase or an aldehyde dehydrogenase. See FIG. 3.

For example, 7-aminoheptanoate and 7-hydroxyheptanoate can be converted to heptamethylenediamine using one or more polypeptides having the activity of a carboxylate reductase, a co-transaminase, an alcohol dehydrogenase, an N-acetyltransferase, and a deacylase. See FIG. 4A-B.

For example, 7-aminoheptanoate can be converted to 7-hydroxyheptanoate using one or more polypeptides having the activity of an alcohol dehydrogenase, a 6-hydroxyhexanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase, a 4-hydroxybutanoate dehydrogenase, or a co-transaminase. See FIG. 5.

For example, 7-aminoheptanoate can be converted to 7-hydroxyheptanoate (see FIG. 5) and subsequently 7-hydroxyheptanoate can be converted to 1,7-heptanediol using polypeptides having the activity of a carboxylate reductase and an alcohol dehydrogenase. See FIG. 6.

The ω-transaminase as described in any of the figures can have at least 70% sequence identity to any one of the amino acid sequences set forth in SEQ ID NO. 7-12. Furthermore, the ω-transaminase as described in any of the figures can have at least 70% sequence identity to any one of the amino acid sequences set forth in SEQ ID NO. 7-12 and be capable of transferring at least one amine group separated from a carboxyl group by at least one methylene insertion.

The carboxylate reductase as described in any of the figures can have at least 70% sequence identity to any one of the amino acid sequences set forth in SEQ ID NO. 2-6 and 15. Furthermore, the carboxylate reductase as described in any of the figures can have at least 70% sequence identity to any one of the amino acid sequences set forth in SEQ D NO. 2-6 and 15 and be capable of reducing a carboxyl group to a terminal aldehyde.

In any of the methods, N-acetyl-3-aminopropanoate can be enzymatically produced from β-alanine, which itself can be enzymatically produced from malonyl-CoA using polypeptides having the activity of a malonyl-CoA reductase and a β-alanine-pyruvate aminotransferase or from L-aspartate using a polypeptide having the activity of an aspartate α-decarboxylase.

In any of the methods described herein, pimelic acid can be produced by forming the second terminal functional group in pimelate semialdehyde (also known as 7-oxoheptanoate) using a polypeptide having the activity of (i) an aldehyde dehydrogenase classified under EC 1.2.1.3, or (ii) a 5-oxopentanoate dehydrogenase classified under EC 1.2.1.- such as encoded by CpnE, a 6-oxohexanoate dehydrogenase classified under EC 1.2.1.63 such as that encoded by ChnE or a 7-oxoheptanoate dehydrogenase classified under EC 1.2.1.- (e.g., the gene product of ThnG). See FIG. 3.

In any of the methods described herein, 7-hydroxyheptanoic acid can be produced by forming the second terminal functional group in pimelate semialdehyde using a polypeptide having the activity of an alcohol dehydrogenase classified under EC 1.1.1.-, 6-hydroxyhexanoate dehydrogenase classified under EC 1.1.1.258 such as the gene product of ChnD (Iwaki et al., Appl. Environ. Microbiol., 1999, 65(11):5158-5162); a 5-hydroxypentanoate dehydrogenase classified under EC 1.1.1.- such as the gene product of cpnD, or 4-hydroxybutanoate dehydrogenase classified under EC 1.1.1.61 such as the gene product of gabD. See FIG. 5.

In any of the methods described herein, heptamethylenediamine can be produced by forming a second terminal functional group in (i) 7-aminoheptanal using a polypeptide having the activity of a ω-transaminase classified under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48 or EC 2.6.1.82 or in (ii) N7-acetyl-1,7-diaminoheptane using a deacylase classified, for example, under EC 3.5.1.62. See FIG. 4B-C.

In any of the methods described herein, 1,7-heptanediol can be produced by forming the second terminal functional group in 7-hydroxyheptanal using a polypeptide having the activity of an alcohol dehydrogenase classified under EC 1.1.1.- (e.g., EC 1.1.1.1, 1.1.1.2, 1.1.1.21, or 1.1.1.184) such as that encoded by YMR318C, YqhD or CAA81612.1. See FIG. 6.

In some embodiments, the biological feedstock can be or can derive from, monosaccharides, disaccharides, lignocellulose, hemicellulose, cellulose, lignin, levulinic acid and formic acid, triglycerides, glycerol, fatty acids, agricultural waste, condensed distillers' solubles, or municipal waste.

In some embodiments, the non-biological feedstock can be or can derive from natural gas, syngas, CO₂/H₂, methanol, ethanol, benzoate, non-volatile residue (NVR) or a caustic wash waste stream from cycloheptane oxidation processes, or terephthalic acid/isophthalic acid mixture waste streams.

In some embodiments, the microorganism's tolerance to high concentrations of one or more C7 (7-carbon) building blocks is improved through continuous cultivation in a selective environment.

In some embodiments, the microorganism's biochemical network is attenuated or augmented to (1) ensure the intracellular availability of acetyl-CoA and β-alanine, (2) create an NADH or NADPH imbalance that may only be balanced via the formation of one or more C7 building blocks, (3) prevent degradation of central metabolites, central precursors leading to and including C7 building blocks and (4) ensure efficient efflux from the cell.

In some embodiments, a cultivation strategy is used to achieve anaerobic, micro-aerobic, or aerobic cultivation conditions.

In some embodiments, the cultivation strategy includes limiting nutrients, such as limiting nitrogen, phosphate or oxygen.

In some embodiments, one or more C7 building blocks are produced by a single type of microorganism, e.g., a recombinant microorganism containing one or more exogenous nucleic acids, using, for example, a fermentation strategy. In some embodiments, one or more C7 building blocks are produced by a single type of microorganism having one or more exogenous nucleic acids which encode a polypeptide having an activity of 3-hydroxyacyl-CoA dehydrogenase, an enoyl-CoA hydratase, a trans-2-enoyl-CoA reductase, a β-ketothiolase, a β-ketoacyl synthase, a thioesterase or a CoA transferase and a deacetylase, using, for example, a fermentation strategy. In another aspect, this document features a recombinant microorganism that includes at least one exogenous nucleic acid encoding a polypeptide having the activity of (i) a β-ketoacyl synthase, (ii) a β-ketothiolase, (iii) a thioesterase or a CoA transferase, (iv) a deacetylase and one or more of (v) a 3-hydroxyacyl-CoA dehydrogenase, (vi) an enoyl-CoA hydratase, and (vii) a trans-2-enoyl-CoA reductase, the microorganism producing 7-aminoheptanoate or a corresponding salt thereof. See FIG. 1 and FIG. 2.

A microorganism producing 7-aminoheptanoate further can include one or more of the following exogenous polypeptides having the activity of: a ω-transaminase, a 7-oxoheptanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, a 5-oxopentanoate dehydrogenase, or an aldehyde dehydrogenase, the microorganism further producing pimelic acid. See FIG. 3.

A microorganism producing 7-aminoheptanoate or 7-hydroxyheptanoate further can include one or more of the following exogenous polypeptides having the activity of: a carboxylate reductase, a ω-transaminase, a deacylase, an N-acetyl transferase, or an alcohol dehydrogenase, said microorganism further producing heptamethylenediamine. See FIG. 4A-B.

A microorganism producing 7-aminoheptanoate further can include one or more of the following exogenous polypeptides having the activity of: a ω-transaminase, a 6-hydroxyhexanoate dehydrogenase, a 4-hydroxybutanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase, and an alcohol dehydrogenase, the microorganism further producing 7-hydroxyheptanoate. See FIG. 5.

A microorganism producing 7-hydroxyheptanoate further can include an exogenous polypeptide having the activity of a carboxylate reductase and an exogenous polypeptide having the activity of an alcohol dehydrogenase, the microorganism further producing 1,7-heptanediol. See FIG. 6.

Any of the recombinant microorganisms described herein further can include one or more of the following exogenous polypeptides having the activity of: an aspartate-α-decarboxylase; a malonyl-CoA reductase; a β-alanine-pyruvate aminotransferase; an N-acetyl transferase; a thioesterase; a CoA-transferase; and a deactylase.

Any of the recombinant microorganisms can be a prokaryote such as a prokaryote from a genus selected from the group consisting of Escherichia; Clostridia; Corynebacteria; Cupriavidus; Pseudomonas; Delftia; Bacilluss; Lactobacillus; Lactococcus; and Rhodococcus. For example, the prokaryote can be selected from the group consisting of Escherichia coli, Clostridium ljungdahlii, Clostridium autoethanogenum, Clostridium kluyveri, Corynebacterium glutamicum, Cupriavidus necator, Cupriavidus metallidurans. Pseudomonas fluorescens, Pseudomonas putida, Pseudomonas oleavorans, Delftia acidovorans, Bacillus subtillis, Lactobacillus delbrueckii, Lactococcus lactis, and Rhodococcus equi. Such prokaryotes also can be sources of genes for constructing recombinant cells described herein that are capable of producing C7 building blocks.

Any of the recombinant microorganisms can be a eukaryote such as a eukaryote from a genus selected from the group consisting of Aspergillus, Saccharomyces, Pichia, Yarrowia, Issatchenkia, Debaryomyces, Arxula, and Kluyveromyces. For example, the eukaryote can be selected from the group consisting of Aspergillus niger, Saccharomyces cerevisiae, Pichia pastoris, Yarrowia hpolytica, Issathenkia orientalis, Debaryomyces hansenii, Arxula adenoinivorans, and Kluyveromyces lactis. Such eukaryotes also can be sources of genes for constructing recombinant cells described herein that are capable of producing C7 building blocks.

Any of the recombinant microorganisms described herein further can include attenuation of one or more of the following enzymes: a polyhydroxyalkanoate synthase, an acetyl-CoA thioesterase, a phosphotransacetylase forming acetate, an acetate kinase, a lactate dehydrogenase, a menaquinol-fumarate oxidoreductase, an alcohol dehydrogenase forming ethanol, a triose phosphate isomerase, a pyruvate decarboxylase, a glucose-6-phosphate isomerase, NADH-consuming transhydrogenase, an NADH-specific glutamate dehydrogenase, a NADH/NADPH-utilizing glutamate dehydrogenase, a pimeloyl-CoA dehydrogenase; an acyl-CoA dehydrogenase accepting C7 building blocks and central precursors as substrates; a butyryl-CoA dehydrogenase; or an adipyl-CoA synthetase.

Any of the recombinant microorganisms described herein further can overexpress one or more genes encoding: an acetyl-CoA synthetase, a 6-phosphogluconate dehydrogenase; a transketolase; a puridine nucleotide transhydrogenase; a glyceraldehyde-3P-dehydrogenase; a malic enzyme; a glucose-6-phosphate dehydrogenase; a glucose dehydrogenase; a fructose 1,6 diphosphatase; a L-alanine dehydrogenase; a L-glutamate dehydrogenase; a formate dehydrogenase; a L-glutamine synthetase; a diamine transporter; a dicarboxylate transporter; and/or a multidrug transporter.

In another aspect of the invention, this document features a non-naturally occurring microorganism comprising at least one exogenous nucleic acid encoding at least one polypeptide having the activity of at least one enzyme, at least one substrate and at least one product, depicted in any one of FIGS. 1 to 6.

In another aspect of the invention, this document features a plurality of nucleic acid constructs or expression vectors comprising a polynucleotide encoding a polypeptide having enzymatic activities corresponding to the polypeptides as set out in SEQ ID NO:1 to SEQ ID NO: 15 and to polypeptides having at least 70% sequence identity to the polypeptides as set out in SEQ ID NO:1 to SEQ ID NO: 15. (See FIG. 7A-E).

In another aspect of the invention, this document features a composition comprising a nucleic acid construct or expression vector comprising a polynucleotide encoding a polypeptide having enzymatic activities corresponding to the polypeptides as set out in SEQ ID NO:1 to SEQ ID NO: 15 and to polypeptides having at least 70% sequence identity to the polypeptides as set out in SEQ ID NO:1 to SEQ ID NO: 15. (See FIG. 7A-E).

In another aspect of the invention, this document features a culture medium comprising a nucleic acid construct or expression vector comprising a polynucleotide encoding a polypeptide having enzymatic activities corresponding to the polypeptides as set out in SEQ ID NO:1 to SEQ ID NO: 15 and to polypeptides having at least 70% sequence identity to the polypeptides as set out in SEQ ID NO:1 to SEQ ID NO: 15. (See FIG. 7A-E).

In another aspect of the invention, this document features a non-naturally occurring biochemical network comprising N-acetyl-3-aminopropanoyl-CoA, an exogenous nucleic acid encoding a polypeptide having the activity of a β-ketothiolase or a β-ketoacyl synthase classified under EC. 2.3.1, and an N-acetyl-5-amino-3-oxopentanoyl-CoA.

In another aspect of the invention, this document features a non-naturally occurring biochemical network comprising at least one exogenous nucleic acid encoding a polypeptide having the enzymatic activity of (i) a β-ketoacyl synthase and/or a β-ketothiolase, (ii) a thioesterase or a CoA transferase, (iii) a deacetylase, and one or more of (iv) 3-hydroxyacyl-CoA dehydrogenase, (iv) an enoyl-CoA hydratase, and (v) a trans-2-enoyl-CoA reductase, said microorganism producing 7-aminoheptanoate.

In another aspect of the invention, this document features means for producing 7-aminoheptanoate, comprising culturing a non-naturally occurring microorganism comprising at least one exogenous nucleic acid encoding a polypeptide having the enzymatic activity of (i) a β-ketoacyl synthase and/or a β-ketothiolase, (ii) a thioesterase or a CoA transferase, (iii) a deacetylase, and one or more of (iv) a 3-hydroxyacyl-CoA dehydrogenase, (iv) an enoyl-CoA hydratase, and (v) a trans-2-enoyl-CoA reductase expressed in a sufficient amount in said microorganism to produce 7-amino-heptanoate.

In another aspect of the invention, this document features a bio-derived, bio-based or fermentation-derived product, wherein said product comprises: i. a composition comprising at least one bio-derived, bio-based or fermentation-derived compound according to any one of original claims 15-28 (numbered according to the as-filed U.S. application Ser. No. 15/368,092 filed Dec. 2, 2016, and published as U.S. 2018/0066296 on Mar. 8, 2018, incorporated herein by reference) or any combination thereof, ii. a bio-derived, bio-based or fermentation-derived polymer comprising the bio-derived, bio-based or fermentation-derived composition or compound of i., or any combination thereof, iii. a bio-derived, bio-based or fermentation-derived resin comprising the bio-derived, bio-based or fermentation-derived compound or bio-derived, bio-based or fermentation-derived composition of i. or any combination thereof or the bio-derived, bio-based or fermentation-derived polymer of ii. or any combination thereof, iv. a molded substance obtained by molding the bio-derived, bio-based or fermentation-derived polymer of ii. or the bio-derived, bio-based or fermentation-derived resin of iii., or any combination thereof, v. a bio-derived, bio-based or fermentation-derived formulation comprising the bio-derived, bio-based or fermentation-derived composition of i., bio-derived, bio-based or fermentation-derived compound of i., bio-derived, bio-based or fermentation-derived polymer of ii., bio-derived, bio-based or fermentation-derived resin of iii., or bio-derived, bio-based or fermentation-derived molded substance of iv, or any combination thereof, or vi. a bio-derived, bio-based or fermentation-derived semi-solid or a non-semi-solid stream, comprising the bio-derived, bio-based or fermentation-derived composition of i., bio-derived, bio-based or fermentation-derived compound of i., bio-derived, bio-based or fermentation-derived polymer of ii., bio-derived, bio-based or fermentation-derived resin of iii., bio-derived, bio-based or fermentation-derived formulation of v., or bio-derived, bio-based or fermentation-derived molded substance of iv., or any combination thereof.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the application, including the written description and drawings, and the claims. The word “comprising” in the claims may be replaced by “consisting essentially of” or with “consisting of,” according to standard practice in patent law.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic of exemplary biochemical pathways leading to N-acetyl-7-aminoheptanoyl-CoA using malonyl-CoA or L-aspartate as central metabolites.

FIG. 2 is a schematic of an exemplary biochemical pathway leading to 7-aminoheptanoate using N-acetyl-7-aminoheptanoyl-CoA as a precursor.

FIG. 3 is a schematic of exemplary biochemical pathways leading to pimelic acid using 7-aminoheptanoate as a central precursor.

FIG. 4A is a schematic of an exemplary biochemical pathway leading to heptamethylenediamine using 7-aminoheptanoate as a central precursor. FIG. 4B is a schematic of an exemplary biochemical pathway leading to heptamethylenediamine using 7-hydroxyheptanoate as a central precursor. FIG. 4C is a schematic of an exemplary biochemical pathway leading to heptamethylenediamine using 7-aminoheptanoate as a central precursor. FIG. 4D is a schematic of an exemplary biochemical pathway leading to heptamethylenediamine using pimelate semialdehyde as a central precursor. FIG. 4E is a schematic of an exemplary biochemical pathway leading to heptamethylenediamine using 1,7 heptanediol as a central precursor.

FIG. 5 is a schematic of exemplary biochemical pathways leading to 7-hydroxyheptanoate using 7-aminoheptanoate as a central precursor.

FIG. 6 is a schematic of an exemplary biochemical pathway leading to 1,7-heptanediol using 7-hydroxyheptanoate as a central precursor.

FIG. 7A-F contains the amino acid sequences of a Cupriavidus necator β-ketothiolase (see GenBank Accession No. AAC38322.1, SEQ ID NO: 1), a Mycobacterium marinum carboxylate reductase (see Genbank Accession No. ACC40567.1, SEQ ID NO: 2), a Mycobacterium smegmatis carboxylate reductase (see Genbank Accession No. ABK71854.1, SEQ ID NO: 3), a Segniliparus rugosus carboxylate reductase (see Genbank Accession No. EFV11917.1, SEQ ID NO: 4), a Mycobacterium massiliense carboxylate reductase (see Genbank Accession No. EIV11143.1, SEQ ID NO: 5), a Segniliparus rotundus carboxylate reductase (see Genbank Accession No. ADG98140.1, SEQ ID NO: 6), a Chromobacterium violaceum ω-transaminase (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 7), a Pseudomonas aeruginosa ω-transaminase (see Genbank Accession No. AAG08191.1, SEQ ID NO: 8), a Pseudomonas syringae ω-transaminase (see Genbank Accession No. AAY39893.1, SEQ ID NO: 9), a Rhodobacter sphaeroides ω-transaminase (see Genbank Accession No. ABA81135.1, SEQ ID NO: 10), an Escherichia coli ω-transaminase (see Genbank Accession No. AAA57874.1, SEQ ID NO: 11), a Vibrio fluvialis ω-transaminase (See Genbank Accession No. AEA39183.1, SEQ ID NO: 1 CAA74523.12), an Escherichia coli β-ketothiolase (see GenBank Accession No. AAC74479.1, SEQ ID NO: 13), a Bacillus subtilis β-ketoacyl synthase (see GenBank Accession No. CAA74523.1, SEQ ID NO: 14), a Mycobacterium smegmatis carboxylate reductase (see GenBank Accession No. ABK75684.1, SEQ ID NO: 15), a Cupriavidus necator beta-ketothiolase (see GenBank Accession No. AAC38322.1, SEQ ID NO: 16), an Escherichia coli (see Genbank Accession No. AAC74479.1, SEQ ID NO: 17), a Clostridium propionicum acetate/propionate CoA transferase (see Genbank Accession No. CAB77207.1, SEQ ID NO: 18), a Clostridium aminobutyricum 4-hydroxybutyrate-CoA transferase (see Genbank Accession No. CAB60036.2, SEQ ID NO: 19), a Citrobacter sp. A1 acetyl-CoA hydrolase/transferase transferase (see Genbank Accession No. EJF23789.1, SEQ ID NO: 20), and an Acetobacter aceti succinyl-CoA:acetate CoA-transferase (see Genbank Accession No. ACD85596.1, SEQ ID NO: 21).

FIG. 8 is a bar graph summarizing the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and activity of six carboxylate reductase preparations in enzyme only controls (no substrate).

FIG. 9 is a bar graph of the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and the activity of two carboxylate reductase preparations for converting pimelate to pimelate semialdehyde relative to the empty vector control.

FIG. 10 is a bar graph of the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and the activity of six carboxylate reductase preparations for converting 7-hydroxyheptanoate to 7-hydroxyheptanal relative to the empty vector control.

FIG. 11 is a bar graph of the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and the activity of three carboxylate reductase preparations for converting N7-acetyl-7-aminoheptanoate to N7-acetyl-7-aminoheptanal relative to the empty vector control.

FIG. 12 is a bar graph of the change in absorbance at 340 nm after 20 minutes, which is a measure of the consumption of NADPH and activity of a carboxylate reductase preparation for converting pimelate semialdehyde to heptanedial relative to the empty vector control.

FIG. 13 is a bar graph summarizing the percent conversion of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity of the enzyme only controls (no substrate).

FIG. 14 is a bar graph of the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity of four ω-transaminase preparations for converting 7-aminoheptanoate to pimelate semialdehyde relative to the empty vector control.

FIG. 15 is a bar graph of the percent conversion after 4 hours of L-alanine to pyruvate (mol/mol) as a measure of the ω-transaminase activity of three ω-transaminase preparations for converting pimelate semialdehyde to 7-aminoheptanoate relative to the empty vector control.

FIG. 16 is a bar graph of the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity of six ω-transaminase preparations for converting heptamethylenediamine to 7-aminoheptanal relative to the empty vector control.

FIG. 17 is a bar graph of the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity of six ω-transaminase preparations for converting N7-acetyl-1,7-diaminoheptane to N7-acetyl-7-aminoheptanal relative to the empty vector control.

FIG. 18 is a bar graph of the percent conversion after 4 hours of pyruvate to L-alanine (mol/mol) as a measure of the ω-transaminase activity of three ω-transaminase preparations for converting 7-aminoheptanol to 7-oxoheptanol relative to the empty vector control.

FIG. 19 is a schematic of the exemplary enzymatic reactions performed with 4-hydroxybutyrate-CoA transferase using either N-acetyl-β-alanine (AC5) or 5-ethanamidopentanoic acid (AC7) as substrates for the formation of 5-ethanamido-3-oxopentanoyl-CoA and 7-ethanamido-3-oxoheptanoyl-CoA, respectively.

FIG. 20 is a LC-MS chromatogram of distinct peaks of chemical abundance separated by retention times as a measure of enzyme activity for of 4-hydroxybutyrate-CoA transferase for converting 5-ethanamidopentanoic acid into products, 5-ethanamidopentanoyl-CoA (g) and 7-ethanamido-3-oxopentanoyl-CoA (h).

FIG. 21 is a LC-MS ESI mass spectrum performed in positive mode that identifies the product of peak (g) (see chromatogram of FIG. 20) as ethanamidopentanoyl-CoA by comparison of the observed and expected masses for the [M+H]⁺ and [M+2H]²⁺ species. Expected [M+H]⁺ for products (g): 909.2017 (1 charge) & [M+2H]²⁺: 445.1044 (2 charges).

FIG. 22 is a LC-MS chromatogram of distinct peaks of chemical abundance separated by retention times as a measure of enzyme activity for of 4-hydroxybutyrate-CoA transferase for converting 5-ethanamidopentanoyl-CoA into the product. 7-ethanamido-3-oxopentanoyl-CoA (h).

FIG. 23 is a LC-MS ESI mass spectrum performed in positive mode that identifies the product of peak (h) (see chromatogram of FIG. 22) as ethanamido-3-oxopentanoyl-CoA by comparison of the observed and expected masses for the [M+H]⁺ and [M+2H]²⁺ species. Expected [M+H]⁺ for products (h): 951.2120 (1 charge) & [M+2H]2+: 476.1097 (2 charges).

DETAILED DESCRIPTION

In general, this document provides enzymes, non-natural pathways, cultivation strategies, feedstocks, microorganisms and attenuations to the microorganism's biochemical network, for producing 7-aminoheptanoate or one or more of pimelic acid, 7-hydroxyheptanoic acid, heptamethylenediamine or 1,7-heptanediol or the corresponding salts thereof, all of which are referred to as C7 building blocks herein. The term “C7 building block” is used to denote a seven (7) carbon chain aliphatic backbone. As used herein, the term “central precursor” is used to denote any metabolite in any metabolic pathway shown herein leading to the synthesis of a C7 building block. The term “central metabolite” is used herein to denote a metabolite that is produced in all microorganisms to support growth.

Microorganisms described herein can include endogenous pathways that can be manipulated such that 7-aminoheptanoate or one or more other C7 building blocks can be produced. In an endogenous pathway, the microorganism naturally expresses all of the enzymes catalyzing the reactions within the pathway. A microorganism containing an engineered pathway does not naturally express all of the enzymes catalyzing the reactions within the pathway but has been engineered such that all of the enzymes within the pathway are expressed in the microorganism.

The term “exogenous” as used herein with reference to a nucleic acid (or a protein) and a microorganism refers to a nucleic acid that does not occur in (and cannot be obtained from) a cell of that particular type as it is found in nature or a protein encoded by such a nucleic acid. Thus, a non-naturally-occurring nucleic acid is considered to be exogenous to a microorganism once in the microorganism. It is important to note that non-naturally-occurring nucleic acids can contain nucleic acid subsequences or fragments of nucleic acid sequences that are found in nature provided the nucleic acid as a whole does not exist in nature. For example, a nucleic acid molecule containing a genomic DNA sequence within an expression vector is non-naturally-occurring nucleic acid, and thus is exogenous to a microorganism once introduced into the microorganism, since that nucleic acid molecule as a whole (genomic DNA plus vector DNA) does not exist in nature. Thus, any vector, autonomously replicating plasmid, or virus (e.g., retrovirus, adenovirus, or herpes virus) that as a whole does not exist in nature is considered to be non-naturally-occurring nucleic acid. It follows that genomic DNA fragments produced by PCR or restriction endonuclease treatment as well as cDNAs are considered to be non-naturally-occurring nucleic acid since they exist as separate molecules not found in nature. It also follows that any nucleic acid containing a promoter sequence and polypeptide-encoding sequence (e.g., cDNA or genomic DNA) in an arrangement not found in nature is non-naturally-occurring nucleic acid. A nucleic acid that is naturally-occurring can be exogenous to a particular microorganism. For example, an entire chromosome isolated from a cell of yeast x is an exogenous nucleic acid with respect to a cell of yeasty once that chromosome is introduced into a cell of yeasty.

In contrast, the term “endogenous” as used herein with reference to a nucleic acid (e.g., a gene) (or a protein) and a microorganism refers to a nucleic acid (or protein) that does occur in (and can be obtained from) that particular microorganism as it is found in nature. Moreover, a cell “endogenously expressing” a nucleic acid (or protein) expresses that nucleic acid (or protein) as does a microorganism of the same particular type as it is found in nature. Moreover, a microorganism “endogenously producing” or that “endogenously produces” a nucleic acid, protein, or other compound produces that nucleic acid, protein, or compound as does a microorganism of the same particular type as it is found in nature.

For example, depending on the microorganism and the compounds produced by the microorganism, one or more of the following polypeptides having the following specific enzymatic activities may be expressed in the microorganism in addition to a β-ketoacyl synthase and/or a β-ketothiolase: a 3-hydroxyacyl-CoA dehydrogenase, an enoyl-CoA hydratase, a trans-2-enoyl-CoA reductase, a thioesterase, a CoA transferase, a deacetylase, an aldehyde dehydrogenase, an alcohol dehydrogenase, a 7-oxoheptanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, a 5-oxopentanoate dehydrogenase, a 6-hydroxyhexanoate dehydrogenase, a 4-hydroxybutanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase, a carboxylate reductase, an N-acetyl transferase, or a ω-transaminase. In recombinant microorganisms expressing a polypeptide having the activity of a carboxylate reductase, a phosphopantetheinyl transferase also can be expressed as it enhances activity of the carboxylate reductase.

For example, a recombinant microorganism can include a polypeptide having the activity of an exogenous β-ketoacyl synthase or a β-ketothiolase and produce N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof from N-acetyl-3-aminopropanoyl-CoA. The N-acetyl-5-amino-3-oxopentanoyl-CoA or salt thereof can be converted enzymatically to N-acetyl-7-aminoheptanoyl-CoA and subsequently to 7-aminoheptanoate.

For example, a recombinant microorganism can include a polypeptide having the activity of an exogenous β-ketoacyl synthase and a β-ketothiolase, an exogenous thioesterase or CoA-transferase, a deacetylase, a 3-hydroxyacyl-CoA dehydrogenase, an enoyl-CoA hydratase, and a trans-2-enoyl-CoA reductase and produce 7-aminoheptanoate.

For example, a recombinant microorganism producing 7-aminoheptanoate can include one or more of the following exogenous polypeptides having the enzymatic activity of: a ω-transaminase, a 7-oxoheptanoate dehydrogenase, a 5-oxopentanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, or an aldehyde dehydrogenase, and further produce pimelic acid. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous ω-transaminase and an aldehyde dehydrogenase and produce pimelic acid. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous polypeptide having the activity of a ω-transaminase and one of the following exogenous polypeptides having the enzymatic activity of: a 5-oxopentanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, or a 7-oxoheptanoate dehydrogenase, and produce pimelic acid.

For example, a recombinant microorganism producing 7-aminoheptanoate can include one or more of the following exogenous polypeptides having the enzymatic activity of: a ω-transaminase, an alcohol dehydrogenase, a 6-hydroxyhexanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase, 4-hydroxybutanoate dehydrogenase, and further produce 7-hydroxyheptanoate. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous polypeptide having the activity of an alcohol dehydrogenase and an exogenous polypeptide having the activity of a ω-transaminase and produce 7-hydroxyheptanoate. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous polypeptide having the activity of a 6-hydroxyhexanoate dehydrogenase and an exogenous polypeptide having the activity of a ω-transaminase and produce 7-hydroxyheptanoate. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous polypeptide having the activity of a 5-hydroxypentanoate dehydrogenase and an exogenous polypeptide having the activity of a ω-transaminase and produce 7-hydroxyheptanoate. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous polypeptide having the activity of a 4-hydroxybutanoate dehydrogenase and an exogenous polypeptide having the activity of a ω-transaminase and produce 7-hydroxyheptanoate.

For example, a recombinant microorganism producing 7-aminoheptanoate can include one or more of the following exogenous polypeptides having the activity of: a carboxylate reductase, a ω-transaminase, a deacetylase, an N-acetyl transferase or an alcohol dehydrogenase, and produce heptamethylenediamine. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous polypeptide having the activity of a carboxylate reductase and one or more exogenous polypeptides having the activity of transaminases (e.g., one ω-transaminase or two different transaminases) and produce heptamethylenediamine. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous polypeptide having the activity of a carboxylate reductase, an exogenous polypeptide having the activity of a alcohol dehydrogenase, and one or more exogenous polypeptides having the activity of transaminases (e.g., one ω-transaminase or two different transaminases), and produce heptamethylenediamine. For example, a recombinant microorganism producing 7-aminoheptanoate can include an exogenous polypeptide having the activity of an N-acetyl transferase, a carboxylate reductase, a deacylase, and one or more exogenous transaminases (e.g., one ω-transaminase or two different transaminases) and produce heptamethylenediamine. For example, a recombinant microorganism producing 7-aminoheptanoate can include one or more exogenous polypeptide having the activity of an alcohol dehydrogenase, and one or more exogenous polypeptides having the activity of transaminases (e.g., one ω-transaminase, or two or three different transaminases) and produce heptamethylenediamine.

For example, a recombinant microorganism producing 7-hydroxyheptanoate can include the following exogenous polypeptides having the enzymatic activity of: a carboxylate reductase and an exogenous alcohol dehydrogenase, and further produce 1,7-heptanediol.

In any of the recombinant microorganisms, the recombinant microorganism also can include one or more (e.g., one, two or three) of the following exogenous enzymes used to convert either malonyl-CoA or L-aspartate to β-alanine: a malonyl-CoA reductase, an aspartate α-decarboxylase and a β-alanine-pyruvate aminotransferase. For example, a recombinant microorganism can include an exogenous malonyl-CoA reductase and a β-alanine-pyruvate aminotransferase and produce β-alanine. For example, a recombinant microorganism can include an exogenous aspartate α-decarboxylase and produce β-alanine.

In any of the recombinant microorganisms, the recombinant microorganism also can include following the exogenous enzyme used to convert β-alanine to N-acetyl-3-aminopropanoate: an N-acetyl-transferase.

In any of the recombinant microorganisms, the recombinant microorganism also can include one or more (e.g., one or two) of the following exogenous enzymes used to convert N-acetyl-3-aminopropanoate to N-acetyl-3-aminopropanoyl-CoA: a CoA transferase or a CoA ligase.

In any of the recombinant microorganisms, the recombinant microorganism also can include one or more (e.g., one or two) of the following exogenous enzymes used to convert 5-ethanamidopentanoic acid to 5-ethanamidopentanoyl-CoA: a CoA transferase or a CoA ligase.

Within an engineered pathway, the enzymes can be from a single source, i.e., from one species or genera, or can be from multiple sources, i.e., different species or genera. Nucleic acids encoding the enzymes described herein have been identified from various organisms and are readily available in publicly available databases such as GenBank or EMBL.

Any of the enzymes described herein that can be used for production of one or more C7 building blocks can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of the corresponding wild-type enzyme. It will be appreciated that the sequence identity can be determined on the basis of the mature enzyme (e.g., with any signal sequence removed) or on the basis of the immature enzyme (e.g., with any signal sequence included). It also will be appreciated that the initial methionine residue may or may not be present on any of the enzyme sequences described herein.

For example, a β-ketothiolase described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Cupriavidus necator β-ketothiolase (see GenBank Accession No. AAC38322.1, SEQ ID NO: 1) or an Escherichia coli β-ketothiolase (see GenBank Accession No. AAC74479.1, SEQ ID NO: 13) See FIG. 7A and FIG. 7E.

For example, a β-ketoacyl synthase described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Bacillus subtilis β-ketoacyl synthase (see GenBank Accession No. CAA74523.1, SEQ ID NO: 14). See FIG. 7E.

For example, a CoA-transferase described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Clostridium aminobutyrium (see GenBank Accession No. CAB60036.2, SEQ ID NO: 19). See FIG. 7F.

For example, a carboxylate reductase described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Mycobacterium marinum carboxylate reductase (see Genbank Accession No. ACC40567.1, SEQ ID NO: 2), a Mycobacterium smegmatis carboxylate reductase (see Genbank Accession No. ABK71854.1, SEQ ID NO: 3), a Segniliparus rugosus carboxylate reductase (see Genbank Accession No. EFV11917.1, SEQ ID NO: 4), a Mycobacterium massiliense carboxylate reductase (see Genbank Accession No. EIV11143.1, SEQ ID NO: 5), a Segnihparus rotundus carboxylate reductase (see Genbank Accession No. ADG98140.1, SEQ ID NO: 6) carboxylate reductase or a Mycobacterium smegmatis carboxylate reductase (see Genbank Accession No. ABK75684.1, SEQ ID NO: 15). See, FIG. 7A-C and FIG. 7E. For example, a ω-transaminase described herein can have at least 70% sequence identity (homology) (e.g., at least 75%, 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 100%) to the amino acid sequence of a Chromobacterium violaceum ω-transaminase (see Genbank Accession No. AAQ59697.1, SEQ ID NO: 7), a Pseudomonas aeruginosa ω-transaminase (see Genbank Accession No. AAG08191.1, SEQ ID NO: 8), a Pseudomonas syringae ω-transaminase (see Genbank Accession No. AAY39893.1, SEQ ID NO: 9), a Rhodobacter sphaeroides ω-transaminase (see Genbank Accession No. ABA81135.1, SEQ ID NO: 10), an Escherichia coli ω-transaminase (see Genbank Accession No. AAA57874.1, SEQ ID NO: 11), or a Vibrio fluvialis (see Genbank Accession No. AEA39183.1, SEQ ID NO: 12) ω-transaminase. Some of these co-transaminases are diamine ω-transaminases. See, FIG. 7D and FIG. 7E.

The percent identity (homology) between two amino acid sequences can be determined as follows. First, the amino acid sequences are aligned using the BLAST 2 Sequences (B12seq) program from the stand-alone version of BLASTZ containing BLASTP version 2.0.14. This stand-alone version of BLASTZ can be obtained from Fish & Richardson's web site (e.g., fr.com/blast/) or the U.S. government's National Center for Biotechnology Information web site (ncbi.nlm.nih.gov). Instructions explaining how to use the Bl2seq program can be found in the readme file accompanying BLASTZ. Bl2seq performs a comparison between two amino acid sequences using the BLASTP algorithm. To compare two amino acid sequences, the options of Bl2seq are set as follows: -i is set to a file containing the first amino acid sequence to be compared (e.g., C:\seq1.txt); -j is set to a file containing the second amino acid sequence to be compared (e.g., C:\seq2.txt); -p is set to blastp; -o is set to any desired file name (e.g., C:\output.txt); and all other options are left at their default setting. For example, the following command can be used to generate an output File containing a comparison between two amino acid sequences: C:\B12seq c:\seq1.txt -j c:\seq2.txt -p blastp -o c:\output.txt. If the two compared sequences share homology (identity), then the designated output file will present those regions of homology as aligned sequences. If the two compared sequences do not share homology (identity), then the designated output file will not present aligned sequences. Similar procedures can be following for nucleic acid sequences except that blastn is used.

Once aligned, the number of matches is determined by counting the number of positions where an identical amino acid residue is presented in both sequences. The percent identity (homology) is determined by dividing the number of matches by the length of the full-length polypeptide amino acid sequence followed by multiplying the resulting value by 100. It is noted that the percent identity (homology) value is rounded to the nearest tenth. For example, 78.11, 78.12, 78.13, and 78.14 is rounded down to 78.1, while 78.15, 78.16, 78.17, 78.18, and 78.19 is rounded up to 78.2. It also is noted that the length value will always be an integer.

It will be appreciated that a number of nucleic acids can encode a polypeptide having a particular amino acid sequence. The degeneracy of the genetic code is well known to the art; i.e., for many amino acids, there is more than one nucleotide triplet that serves as the codon for the amino acid. For example, codons in the coding sequence for a given enzyme can be modified such that optimal expression in a particular species (e.g., bacteria or fungus) is obtained, using appropriate codon bias tables for that species.

Functional fragments of any of the enzymes described herein can also be used in the methods of the document. The term “functional fragment” as used herein refers to a peptide fragment of a protein that has at least 25% (e.g., at least: 30%; 40%; 50%; 60%; 70%; 75%; 80%; 85%; 90%; 95%; 98%; 99%; 100%; or even greater than 100%) of the activity of the corresponding mature, full-length, wild-type protein. The functional fragment can generally, but not always, be comprised of a continuous region of the protein, wherein the region has functional activity.

This document also provides (i) functional variants of the enzymes used in the methods of the document and (ii) functional variants of the functional fragments described above. Functional variants of the enzymes and functional fragments can contain additions, deletions, or substitutions relative to the corresponding wild-type sequences. Enzymes with substitutions will generally have not more than 100 (e.g., not more than one, two, three, four, five, six, seven, eight, nine, ten, 12, 15, 20, 25, 30, 35, 40, 50 or 100) amino acid substitutions (e.g., conservative substitutions). This applies to any of the enzymes described herein and functional fragments. A conservative substitution is a substitution of one amino acid for another with similar characteristics. Conservative substitutions include substitutions within the following groups: valine, alanine and glycine; leucine, valine, and isoleucine; aspartic acid and glutamic acid; asparagine and glutamine; serine, cysteine, and threonine; lysine and arginine; and phenylalanine and tyrosine. The nonpolar hydrophobic amino acids include alanine, leucine, isoleucine, valine, proline, phenylalanine, tryptophan and methionine. The polar neutral amino acids include glycine, serine, threonine, cysteine, tyrosine, asparagine and glutamine. The positively charged (basic) amino acids include arginine, lysine and histidine. The negatively charged (acidic) amino acids include aspartic acid and glutamic acid. Any substitution of one member of the above-mentioned polar, basic or acidic groups by another member of the same group can be deemed a conservative substitution. By contrast, a nonconservative substitution is a substitution of one amino acid for another with dissimilar characteristics.

Deletion variants can lack one, two, three, four, five, six, seven, eight, nine, ten, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 50 amino acid segments (of two or more amino acids) or non-contiguous single amino acids. Additions (addition variants) include fusion proteins containing: (a) any of the enzymes described herein or a fragment thereof; and (b) internal or terminal (C or N) irrelevant or heterologous amino acid sequences. In the context of such fusion proteins, the term “heterologous amino acid sequences” refers to an amino acid sequence other than (a). A heterologous sequence can be, for example a sequence used for purification of the recombinant protein (e.g., FLAG, polyhistidine (e.g., heptahistidine (SEQ ID NO: 22)), hemagglutinin (HA), glutathione-S-transferase (GST), or maltosebinding protein (MBP)). Heterologous sequences also can be proteins useful as detectable markers, for example, luciferase, green fluorescent protein (GFP), or chloramphenicol acetyl transferase (CAT). In some embodiments, the fusion protein contains a signal sequence from another protein. In certain microorganisms (e.g., yeast cells), expression and/or secretion of the target protein can be increased through use of a heterologous signal sequence. In some embodiments, the fusion protein can contain a carrier (e.g., KLH) useful, e.g., in eliciting an immune response for antibody generation) or ER or Golgi apparatus retention signals. Heterologous sequences can be of varying length and in some cases can be a longer sequences than the full-length target proteins to which the heterologous sequences are attached.

Engineered microorganisms can naturally express none or some (e.g., one or more, two or more, three or more, four or more, five or more, or six or more) of the enzymes of the pathways described herein. Thus, a pathway within an engineered microorganism can include all exogenous enzymes, or can include both endogenous and exogenous enzymes. Endogenous genes of the engineered microorganisms also can be disrupted to prevent the formation of undesirable metabolites or prevent the loss of intermediates in the pathway through other enzymes acting on such intermediates. Engineered microorganisms can be referred to as recombinant microorganisms or recombinant cells. As described herein recombinant microorganisms can include nucleic acids encoding one or more of a β-ketoacyl synthase, a β-ketothiolase, a dehydrogenase, a reductase, a hydratase, a CoA-transferase, a CoA-ligase, a thioesterase, a deacetylase, an N-acetyltransferase and co-transaminase as described herein.

In addition, the production of C7 building blocks can be performed in vitro using the isolated enzymes described herein, using a lysate (e.g., a cell lysate) from a microorganism as a source of the enzymes, or using a plurality of lysates from different microorganisms as the source of the enzymes.

The reactions of the pathways described herein can be performed in one or more microorganisms (a) naturally expressing one or more relevant enzymes, (b) genetically engineered to express one or more relevant enzymes, or (c) naturally expressing one or more relevant enzymes and genetically engineered to express one or more relevant enzymes. Alternatively, relevant enzymes can be isolated, purified or extracted from of the above types of microorganism cells and used in a purified or semi-purified form. Moreover, such extracts include lysates (e.g. cell lysates) that can be used as sources of relevant enzymes. In the methods provided by the document, all the steps can be performed in microorganism cells, all the steps can be performed using extracted enzymes, or some of the steps can be performed in cells and others can be performed using extracted enzymes.

Enzymes

Enzymes Generating N-acetyl-7-amino-heptanoyl-CoA

As depicted in FIG. 1, N-acetyl-7-amino-heptanoyl-CoA or a salt thereof can be biosynthesized from malonyl-CoA or L-aspartate through the intermediate N-acetyl-5-amino-3-oxopentanoyl-CoA, which can be produced from N-acetyl-3-aminopropanoyl-CoA using a polypeptide having the activity of a β-ketoacyl synthase or a β-ketothiolase. In some embodiments, a β-ketothiolase may be classified under EC 2.3.1.16, such as the gene product of bktB or under EC 2.3.1.174 such as the gene product of paaf. In some embodiments, a β-ketoacyl synthase may be classified under EC 2.3.1.180 such as the gene product of fabH, under EC 2.3.1.179 such as the gene product of fabF or under EC 2.3.1.41 such as the gene product of fabB.

N-acetyl-3-aminopropanoyl-CoA or a salt thereof can be enzymatically converted from N-acetyl-3-aminopropanoate using a polypeptide having the activity of a CoA transferase classified, for example, under EC 2.8.3- or a CoA ligase classified, for example, under EC 6.2.1-. N-acetyl-3-aminopropanoate can be enzymatically produced from β-alanine using a polypeptide having the activity of an N-acetyl transferase classified, for example, under EC 2.3.1.-, such as EC 2.3.1.13, EC 2.3.1.17 or EC 2.3.1.32.

β-alanine itself can be enzymatically produced from malonyl-CoA using polypeptides having the activity of a malonyl-CoA-reductase and a β-alanine-pyruvate aminotransferase or from L-aspartate using a polypeptide having the activity of an α-aspartate decarboxylase. In some embodiments, a malonyl-CoA-reductase may be classified under EC 1.2.1.75 and a β-alanine-pyruvate aminotransferase may be classified under EC 2.6.1.18. In some embodiments, an α-aspartate decarboxylase may be classified under EC 4.1.1.11.

The intermediate N-acetyl-5-amino-3-oxopentanoyl-CoA or salt thereof can be converted to N-acetyl-7-amino-heptanoyl-CoA using polypeptides having the activity of a 3-hydroxyacyl-CoA dehydrogenase, an enoyl-CoA hydratase, a trans-2-enoyl-CoA reductase and a β-ketothiolase. In some embodiments, a 3-hydroxyacyl-CoA dehydrogenase may be classified, for example, under EC 1.1.1.- such as EC 1.1.1.35 (e.g., the gene product of fadB), EC 1.1.1.36 (e.g., the gene product of phaB), or EC 1.1.1.157 (e.g., the gene product of hbd). In some embodiments, an enoyl-CoA hydratase may be classified under EC 4.2.1.17 such as the gene product of crt or under EC 4.2.1.119 such as the gene product of phaJ. In some embodiments, a trans-2-enoyl-CoA reductase may be classified, for example, under EC 1.3.1.38 or EC 1.3.1.44, such as the gene product of ter (Nishimaki et al., J. Biochem., 1984, 95:1315-1321; Shen et al., 2011, supra) or tdter (Bond-Watts et al., Biochemistry, 2012, 51:6827-6837) or EC 1.3.1.8 (Inui et al., Eur. J. Biochem., 1984, 142, 121-126). In some embodiments, a β-ketothiolase may be classified under EC 2.3.1.16 such as the gene product of bktB or under EC 2.3.1.174 such as the gene product of paaJ.

Enzymes Generating 7-aminoheptanoate

As depicted in FIG. 2, N-acetyl-7-amino-heptanoyl-CoA is converted to 7-aminoheptanoate using polypeptides having the activity of a thioesterase or CoA-transferase and a deacetylase.

In some embodiments, a thioesterase may be classified under EC 3.1.2.-, resulting in the production of N-acetyl-7-aminoheptanoate. The thioesterase can be the gene product of YciA or Acot13 (Cantu et al., Protein Science, 2010, 19, 1281-1295; Zhuang et al., Biochemistry, 2008, 47(9):2789-2796; Naggert et al., J. Biol. Chem., 1991, 266(17):11044-11050). In some embodiments, a CoA-transferase may be classified under, for example, EC 2.8.3.- such as the gene product of cat2 from Clostridium kluyveri, abfT from Clostridium aminobutyricum or the 4-hydroxybutyrate CoA-transferase from Clostridium viride.

In some embodiments, the first terminal amine group leading to the synthesis of 7-aminoheptanoate is enzymatically formed by a deacetylase classified, for example, under EC 3.5.1.17 such as an acyl-lysine deacetylase from Achromobacter pestifer (see, for example, Chibate et al., 1970, Methods Enzymol., 19:756-762).

Enzymes Generating the Terminal Carboxyl Groups in the Biosynthesis of Pimelic Acid

As depicted in FIG. 3, 7-aminoheptanoate can be enzymatically converted to pimelic acid. The terminal carboxyl group leading to the production of pimelic acid can be enzymatically formed using polypeptides having the activity of an aldehyde dehydrogenase, a 5-oxopentanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, or a 7-oxoheptanoate dehydrogenase.

In some embodiments, the second terminal carboxyl group leading to the synthesis of pimelic acid can be enzymatically formed in pimelate semialdehyde by an aldehyde dehydrogenase classified under EC 1.2.1.3 (Guerrillot & Vandecasteele, Eur. J. Biochem., 1977, 81, 185-192). See, FIG. 3.

In some embodiments, the second terminal carboxyl group leading to the synthesis of pimelic acid is enzymatically formed in pimelate semialdehyde by EC 1.2.1.- such as a 5-oxopentanoate dehydrogenase classified, for example, under EC 1.2.1.20, such as the gene product of CpnE, a 6-oxohexanoate dehydrogenase classified, for example, EC 1.2.1.63 such as the gene product of ChnE from Acinetobacter sp., or a 7-oxoheptanoate dehydrogenase such as the gene product of ThnG from Sphingomonas macrogolitabida (Iwaki et al., Appl. Environ. Microbiol., 1999, 65(11), 5158-5162; Lopez-Sanchez et al., Appl. Environ. Microbiol., 2010, 76(1), 110-118)). See, FIG. 3.

Enzymes Generating the Terminal Amine Groups in the Biosynthesis of Heptamethylenediamine

As depicted in FIG. 4A-E, terminal amine groups can be enzymatically formed or removed using polypeptides having the activity of a ω-transaminase or a deacetylase.

In some embodiments, a terminal amine group leading to the synthesis of 7-aminoheptanoic acid is enzymatically formed in 7-aminoheptanal by a ω-transaminase classified, for example, under EC 2.6.1.-, e.g., EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as that obtained from Chromobacterium violaceum (Genbank Accession No. AAQ59697.1, SEQ ID NO: 7), Pseudomonas aeruginosa (Genbank Accession No. AAG08191.1, SEQ ID NO: 8), Pseudomonas syringae (Genbank Accession No. AAY39893.1, SEQ ID NO: 9), Rhodobacter sphaeroides (Genbank Accession No. ABA81135.1, SEQ ID NO: 10), Vibrio fluvialis (Genbank Accession No. AEA39183.1, SEQ ID NO: 12), Streptomyces griseus, or Clostridium viride. See FIG. 7.

An additional ω-transaminase that can be used in the methods and microorganisms described herein is from Escherichia coli (Genbank Accession No. AAA57874.1, SEQ ID NO: 11). Some of the ω-transaminases classified, for example, under EC 2.6.1.29 or EC 2.6.1.82 are diamine ω-transaminases (e.g., SEQ ID NO: 11).

The reversible ω-transaminase from Chromobacterium violaceum (Genbank Accession No. AAQ59697.1, SEQ ID NO: 7) has demonstrated analogous activity accepting 7-aminoheptanoic acid as amino donor, thus forming the first terminal amine group in pimelate semialdehyde (Kaulmann et al., Enzyme and Microbial Technology, 2007, 41, 628-637).

The reversible 4-aminobubyrate:2-oxoadipate transaminase from Streptomyces griseus has demonstrated activity for the conversion of 7-aminoheptanoate to pimelate semialdehyde (Yonaha et al., Eur. J. Biochem., 1985, 146, 101-106).

The reversible 5-aminovalerate transaminase from Clostridium viride has demonstrated activity for the conversion of 7-aminoheptanoate to pimelate semialdehyde (Barker et al., J. Biol. Chem., 1987, 262(19), 8994-9003).

In some embodiments, the second terminal amine group leading to the synthesis of heptamethylenediamine is enzymatically formed in 7-aminoheptanal by a diamine transaminase classified, for example, under EC 2.6.1.29 or classified, for example, under EC 2.6.1.82, such as the gene product of YgjG from E. coli (Genbank Accession No. AAA57874.1, SEQ ID NO: 12). The transaminases set forth in SEQ ID NOs:7-10 and 11 also can be used to produce heptamethylenediamine. See, FIG. 7.

The gene product of ygjG accepts a broad range of diamine carbon chain length substrates, such as putrescine, cadaverine and spermidine (Samsonova et al., BMC Microbiology, 2003, 3:2).

The diamine transaminase from E. coli strain B has demonstrated activity for 1,7 diaminoheptane (Kim, The Journal of Chemistry, 1964, 239(3), 783-786).

In some embodiments, the second terminal amine group leading to the synthesis of heptamethylenediamine is enzymatically formed by a deacetylase classified, for example, under EC 3.5.1.62 such as an acetylputrescine deacetylase. The acetylputrescine deacetylase from Micrococcus luteus K-11 accepts a broad range of carbon chain length substrates, such as acetylputrescine, acetylcadaverine and N8 acetylspermidine (see, for example, Suzuki et al., 1986, BBA—General Subjects, 882(1):140-142).

Enzymes Generating the Terminal Hydroxyl Groups in the Biosynthesis of 1,7 heptanediol

As depicted in FIG. 6, the terminal hydroxyl group can be enzymatically formed using a polypeptide having the activity of an alcohol dehydrogenase. For example, the second terminal hydroxyl group leading to the synthesis of 1,7 heptanediol can be enzymatically formed in 7-hydroxyheptanal by an alcohol dehydrogenase classified under EC 1.1.1.- (e.g., EC 1.1.1.1, 1.1.1.2, 1.1.1.21, or 1.1.1.184) such as the gene product of YMR318C or YqhD (Liu et al., Microbiology, 2009, 155, 2078-2085; Larroy et al., 2002, Biochem J., 361(Pt 1), 163-172; Jarboe, 2011, Appl. Microbiol. Biotechnol., 89(2), 249-257) or the protein having GenBank Accession No. CAA81612.1.

Enzymes Generating N-acetyl-7-amino-3-oxoheptanoyl-CoA

As depicted in FIG. 1, N-acetyl-7-amino-oxoheptanoyl-CoA or a salt thereof can be biosynthesized from malonyl-CoA or L-aspartate through the intermediate N-acetyl-5-amino-3-oxopentanoyl-CoA, which can be produced from N-acetyl-5-aminopentanoyl-CoA using a polypeptide having the activity of a β-ketoacyl synthase, a β-ketothiolase, or a CoA-transferase. In some embodiments, a β-ketothiolase may be classified under EC 2.3.1.16, such as the gene product of bktB or under EC 2.3.1.174 such as the gene product of paaf. In some embodiments, a β-ketoacyl synthase may be classified under EC 2.3.1.180 such as the gene product of fabH, under EC 2.3.1.179 such as the gene product of fabF or under EC 2.3.1.41 such as the gene product of fabB. In some embodiments, a CoA-transferase may be classified under EC 2.8.3- such as the gene product of Off

Biochemical Pathways

Pathways to 7-aminoheptanoate

In some embodiments, N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof is synthesized from the central metabolite, malonyl-CoA, by conversion of malonyl-CoA to malonate semialdehyde by a polypeptide having the activity of a malonyl CoA reductase classified, for example, under EC 1.2.1.75; followed by conversion of malonate semialdehyde to β-alanine by a polypeptide having the activity of a β-alanine-pyruvate aminotransferase classified, for example, under EC 2.6.1.18; followed by conversion of β-alanine to N-acetyl-3-aminopropanoate by a polypeptide having the activity of an N-acetyl transferase classified, for example, under EC 2.3.1.13, EC 2.3.1.17 or EC 2.3.1.32; followed by conversion of N-acetyl-3-aminopropanoate to N-acetyl-3-aminopropanoyl-CoA by a polypeptide having the activity of a CoA transferase classified, for example, under EC 2.8.3.- or a polypeptide having the activity of a CoA ligase classified, for example, under EC 6.2.1.-; followed by conversion of N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA by a polypeptide having the activity of a β-ketoacyl synthase classified under EC. 2.3.1.- (e.g., EC 2.3.1.180) or a polypeptide having the activity of a β-ketothiolase classified under EC. 2.3.1.- (e.g., EC 2.3.1.16 or EC 2.3.1.174).

In some embodiments, N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof is synthesized from the central metabolite, L-aspartate, by conversion of L-aspartate to β-alanine by a polypeptide having the activity of an aspartate α-decarboxylase classified, for example, under EC 4.1.1.11; followed by conversion of β-alanine to N-acetyl-3-aminopropanoate by a polypeptide having the activity of an N-acetyl transferase classified, for example, under EC 2.3.1.13, EC 2.3.1.17 or EC 2.3.1.32; followed by conversion of N-acetyl-3-aminopropanoate to N-acetyl-3-aminopropanoyl-CoA by a polypeptide having the activity of a CoA transferase classified, for example, under EC 2.8.3.- or a polypeptide having the activity of a CoA ligase classified, for example, under EC 6.2.1.-; followed by conversion of N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA by a polypeptide having the activity of a β-ketoacyl synthase classified, for example, under EC 2.3.1.180 such as the gene product of fabH or by a polypeptide having the activity of a β-ketothiolase classified, for example, under EC 2.3.1.16 such as the gene product of bktB or under EC 2.3.1.174 such as the gene product of paaJ.

The intermediate N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof is converted to N-acetyl-5-amino-3-hydroxypentanoyl-CoA by a polypeptide having the activity of a 3-hydroxyacyl-CoA dehydrogenase classified, for example, under EC 1.1.1.-such as EC 1.1.1.35 (e.g., the gene product of fadB), EC 1.1.1.36 (e.g., the gene product of phaB), or EC 1.1.1.157 (e.g., the gene product of hbd); followed by conversion of N-acetyl-5-amino-3-hydroxypentanoyl-CoA to N-acetyl-5-amino-pent-2-enoyl-CoA using a polypeptide having the activity of an enoyl-CoA hydratase classified under, for example, EC 4.2.1.17 such as the gene product of crt or under EC 4.2.1.119 such as the gene product of phaJ; followed by conversion of N-acetyl-5-amino-pent-2-enoyl-CoA to N-acetyl-5-amino-pentanoyl-CoA by a polypeptide having the activity of a trans-2-enoyl-CoA reductase classified under EC 1.3.1.38 or EC 1.3.1.44, such as the gene product of ter (Nishimaki et al., J. Biochem., 1984, 95:1315-1321; Shen et al., 2011, supra) or tdter (Bond-Watts et al., Biochemistry, 2012, 51:6827-6837) or EC 1.3.1.8 (Inui et al., Eur. J. Biochem., 1984, 142, 121-126); followed by conversion of N-acetyl-5-amino-pentanoyl-CoA to N-acetyl-7-amino-3-oxoheptanoyl-CoA by a polypeptide having the activity of a β-ketothiolase classified under, for example, EC 2.3.1.16 such as the gene product of bktB or under EC 2.3.1.174 such as the gene product of paaf; followed by conversion of N-acetyl-7-amino-3-oxoheptanoyl-CoA to N-acetyl-7-amino-3-hydroxyheptanoyl-CoA by a polypeptide having the activity of a 3-hydroxyacyl-CoA dehydrogenase classified, for example, under EC 1.1.1.- such as EC 1.1.1.35 (e.g., the gene product of fadB), EC 1.1.1.36 (e.g., the gene product of phaB), or EC 1.1.1.157 (e.g., the gene product of hbd); followed by conversion of N-acetyl-7-amino-3-hydroxyheptanoyl-CoA to N-acetyl-7-amino-hept-2-enoyl-CoA by a polypeptide having the activity of an enoyl-CoA-hydratase classified under, for example, EC 4.2.1.17 such as the gene product of crt or under EC 4.2.1.119 such as the gene product of phaJ; followed by conversion of N-acetyl-7-amino-hept-2-enoyl-CoA to N-acetyl-7-aminoheptanoyl-CoA by a polypeptide having the activity of a trans-2-enoyl-CoA-reductase classified under EC 1.3.1.38 or EC 1.3.1.44, such as the gene product of ter (Nishimaki et al., J. Biochem., 1984, 95:1315-1321; Shen et al., 2011, supra) or tdter (Bond-Watts et al., Biochemistry, 2012, 51:6827-6837) or EC 1.3.1.8 (Inui et al., Eur. J. Biochem., 1984, 142, 121-126). See FIG. 1.

N-acetyl-7-aminoheptanoyl-CoA is then converted to 7-aminoheptanoate by a polypeptide having the activity of a thioesterase classified, for example, under EC 3.1.2.- or a CoA-transferase classified, for example, under EC 2.8.3.- and subsequently a polypeptide having the activity of a deacetylase classified, for example, under EC 3.5.1.17 such as an acyl-lysine deacetylase from Achromobacter pestifer (see, for example, Chibate et al., 1970, Methods Enzymol., 19:756-762). See FIG. 2.

Pathways Using 7-aminoheptanoate as Central Precursor to Pimelic Acid

In some embodiments, pimelic acid is synthesized from 7-aminoheptanoate, by conversion of 7-aminoheptanoate to pimelate semialdehyde by a polypeptide having the activity of a ω-transaminase classified, for example, under EC 2.6.1.-, e.g., EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as that obtained from Chromobacterium violaceum (Genbank Accession No. AAQ59697.1, SEQ ID NO: 7), Pseudomonas aeruginosa (Genbank Accession No. AAG08191.1, SEQ ID NO: 8), Pseudomonas syringae (Genbank Accession No. AAY39893.1, SEQ ID NO: 9), Rhodobacter sphaeroides (Genbank Accession No. ABA81135.1, SEQ ID NO: 10), Vibrio fluvialis (Genbank Accession No. AEA39183.1, SEQ ID NO: 12), Streptomyces griseus, or Clostridium viride. See, FIG. 3.

Pimelate semialdehyde is then converted to pimelic acid by a polypeptide having the activity of a dehydrogenase classified, for example, under EC 1.2.1.- such as a 7-oxoheptanoate dehydrogenase (e.g., the gene product of ThnG), a 6-oxohexanoate dehydrogenase (e.g., the gene product of ChnE), a glutarate semialdehyde dehydrogenase classified, for example, under EC 1.2.1.20, a 5-oxopentanoate dehydrogenase such as the gene product of CpnE, or an aldehyde dehydrogenase classified under EC 1.2.1.3. See FIG. 3.

Pathway Using 7-aminoheptanoate as Central Precursor to 7-hydroxyheptanoate

In some embodiments, 7-hydroxyheptanoate is synthesized from the central precursor, 7-aminoheptanoate, by conversion of 7-aminoheptanoate to pimelate semialdehyde by a polypeptide having the activity of a ω-transaminase classified, for example, under EC 2.6.1.-, e.g., EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as that obtained from Chromobacterium violaceum (Genbank Accession No. AAQ59697.1, SEQ ID NO: 7), Pseudomonas aeruginosa (Genbank Accession No. AAG08191.1, SEQ ID NO: 8), Pseudomonas syringae (Genbank Accession No. AAY39893.1, SEQ ID NO: 9), Rhodobacter sphaeroides (Genbank Accession No. ABA81135.1, SEQ ID NO: 10), Vibrio fluvialis (Genbank Accession No. AEA39183.1, SEQ ID NO: 12), Streptomyces griseus, or Clostridium viride; followed by conversion of pimelate semialdehyde to 7-hydroxyheptanoate by a polypeptide having the activity of an alcohol dehydrogenase classified, for example, under EC 1.1.1.2 such as the gene product of YMR318C, a 6-hydroxyhexanoate dehydrogenase classified, for example, under EC 1.1.1.258, a 5-hydroxypentanoate dehydrogenase classified, for example, under EC 1.1.1.-such as the gene product of cpnD, or a 4-hydroxybutanoate dehydrogenase classified, for example, under EC 1.1.1.- such as the gene product of gabD. The alcohol dehydrogenase encoded by YMR318C has broad substrate specificity, including the oxidation of C7 alcohols. See FIG. 5.

Pathway Using 7-aminoheptanoate, 7-hydroxyheptanoate, Pimelate Semialdehyde, or 1,7-heptanediol as a Central Precursor to Heptamethylenediamine

In some embodiments, heptamethylenediamine is synthesized from the central precursor, 7-aminoheptanoate, by conversion of 7-aminoheptanoate to 7-aminoheptanal by a polypeptide having the activity of a carboxylate reductase classified, for example, under EC 1.2.99.6 such as the gene product of car in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp gene from Bacillus subtilis or npt gene from Nocardia) or the gene products of GriC and GriD from Streptomyces griseus (Suzuki et al., J. Antibiot., 2007, 60(6), 380-387); followed by conversion of 7-aminoheptanal to heptamethylenediamine by a polypeptide having the activity of a ω-transaminase such as a ω-transaminase in EC 2.6.1.-, (e.g., EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.48, EC 2.6.1.82 such as SEQ ID NOs:7-12). The carboxylate reductase can be obtained, for example, from Mycobacterium marinum (Genbank Accession No. ACC40567.1, SEQ ID NO: 2), Mycobacterium smegmatis (Genbank Accession No. ABK71854.1, SEQ ID NO: 3), Segniliparus rugosus (Genbank Accession No. EFV11917.1, SEQ ID NO: 4), Mycobacterium massiliense (Genbank Accession No. EIV11143.1, SEQ ID NO: 5), Segniliparus rotundus (Genbank Accession No. ADG98140.1, SEQ ID NO: 6) or Mycobacterium smegmatis (Genbank Accession No. ABK75684.1, SEQ ID NO: 15). See FIG. 4A-E.

The carboxylate reductase encoded by the gene product of car and enhancer npt or sfp has broad substrate specificity, including terminal difunctional C4 and C5 carboxylic acids (Venkitasubramanian et al., Enzyme and Microbial Technology, 2008, 42, 130-137).

In some embodiments, heptamethylenediamine is synthesized from the central precursor, 7-hydroxyheptanoate (which can be produced as described in FIGS. 1, 2 and 5), by conversion of 7-hydroxyheptanoate to 7-hydroxyheptanal by a carboxylate reductase classified, for example, under EC 1.2.99.6 such as the gene product of car (see above) in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp gene from Bacillus subtilis or npt gene from Nocardia) or the gene product of GriC & GriD (Suzuki et al., 2007, supra); followed by conversion of 7-aminoheptanal to 7-aminoheptanol by a ω-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as SEQ ID NOs:7-12, see above; followed by conversion to 7-aminoheptanal by an alcohol dehydrogenase classified, for example, under EC 1.1.1.- (e.g., EC 1.1.1.1, EC 1.1.1.2, EC 1.1.1.21, or EC 1.1.1.184) such as the gene product of YMR318C or YqhD (Liu et al., Microbiology, 2009, 155, 2078-2085; Larroy et al., 2002, Biochem 361(Pt 1), 163-172; Jarboe, 2011, Appl. Microbiol. Biotechnol., 89(2), 249-257) or the protein having GenBank Accession No. CAA81612.1; followed by conversion to heptamethylenediamine by a ω-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as SEQ ID NOs:7-12, see above. See FIG. 4C.

In some embodiments, heptamethylenediamine is synthesized from the central precursor, 7-aminoheptanoate, by conversion of 7-aminoheptanoate to N7-acetyl-7-aminoheptanoate by a polypeptide having the activity of an N-acetyltransferase such as a lysine N-acetyltransferase classified, for example, under EC 2.3.1.32; followed by conversion to N7-acetyl-7-aminoheptanal by a polypeptide having the activity of a carboxylate reductase classified, for example, under EC 1.2.99.6 such as the gene product of car (see above, e.g., SEQ ID NO: 4, 5, or 6) in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp gene from Bacillus subtilis or npt gene from Nocardia) or the gene product of GriC & GriD; followed by conversion to N7-acetyl-1,7-diaminoheptane by a polypeptide having the activity of a ω-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as SEQ ID NOs:7-12, see above; followed by conversion to heptamethylenediamine by a polypeptide having the activity of a deacetylase classified, for example, under EC 3.5.1.62 such as an acetylputrescine deacetylase. The acetylputrescine deacetylase from Micrococcus luteus K-11 accepts a broad range of carbon chain length substrates, such as acetylputrescine, acetylcadaverine and N8 acetylspermidine (see, for example, Suzuki et al., 1986, BBA—General Subjects, 882(1):140-142). See, FIG. 4C.

In some embodiments, heptamethylenediamine is synthesized from the central precursor, pimelate semialdehyde, by conversion of pimelate semialdehyde to heptanedial by a polypeptide having the activity of a carboxylate reductase classified, for example, under EC 1.2.99.6 such as the gene product of car (see above, e.g., SEQ ID NO:6) in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp gene from Bacillus subtilis or npt gene from Nocardia) or the gene product of GriC & GriD; followed by conversion to 7-aminoheptanal by a polypeptide having the activity of a co-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82; followed by conversion to heptamethylenediamine by a co-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as SEQ ID NOs:7-12. See FIG. 4D.

In some embodiments, heptamethylenediamine is synthesized from 1,7-heptanediol by conversion of 1,7-heptanediol to 7-hydroxyheptanal using a polypeptide having the activity of an alcohol dehydrogenase classified, for example, under EC 1.1.1.- (e.g., EC 1.1.1.1, EC 1.1.1.2, EC 1.1.1.21, or EC 1.1.1.184) such as the gene product of YMR318C or YqhD or the protein having GenBank Accession No. CAA81612.1; followed by conversion to 7-aminoheptanol by a polypeptide having the activity of a ω-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as SEQ ID NOs:7-12; followed by conversion to 7-aminoheptanal by a polypeptide having the activity of an alcohol dehydrogenase classified, for example, under EC 1.1.1.- (e.g., EC 1.1.1.1, EC 1.1.1.2, EC 1.1.1.21, or EC 1.1.1.184) such as the gene product of YMR318C or YqhD or the protein having GenBank Accession No. CAA81612.1, followed by conversion to heptamethylenediamine by a polypeptide having the activity of a ω-transaminase classified, for example, under EC 2.6.1.18, EC 2.6.1.19, EC 2.6.1.29, EC 2.6.1.48, or EC 2.6.1.82 such as SEQ ID NOs:7-12. See FIG. 4E.

Pathways Using 7-hydroxyheptanoate as Central Precursor to 1,7-heptanediol

In some embodiments, 1,7 heptanediol is synthesized from the central precursor, 7-hydroxyheptanoate, by conversion of 7-hydroxyheptanoate to 7-hydroxyheptanal by a polypeptide having the activity of a carboxylate reductase classified, for example, under EC 1.2.99.6 such as the gene product of car (see above, e.g., SEQ ID NO: 2, 3, 4, 5, or 6) in combination with a phosphopantetheine transferase enhancer (e.g., encoded by a sfp gene from Bacillus subtilis or npt gene from Nocardia) or the gene products of GriC and GriD from Streptomyces griseus (Suzuki et al., J. Antibiot., 2007, 60(6), 380-387); followed by conversion of 7-hydroxyheptanal to 1,7 heptanediol by a polypeptide having the activity of an alcohol dehydrogenase (classified, for example, under EC 1.1.1.- such as EC 1.1.1.1, EC 1.1.1.2, EC 1.1.1.21, or EC 1.1.1.184) such as the gene product of YMR318C or YqhD (from E. coli, GenBank Accession No. AAA69178.1) (see, e.g., Liu et al., Microbiology, 2009, 155, 2078-2085; Larroy et al., 2002, Biochem J., 361(Pt 1), 163-172; or Jarboe, 2011, Appl. Microbiol. Biotechnol., 89(2), 249-257) or the protein having GenBank Accession No. CAA81612.1 (from Geobacillus stearothermophilus). See, FIG. 6.

Cultivation Strategy

In some embodiments, one or more C7 building blocks are biosynthesized in a recombinant microorganism using anaerobic, aerobic or micro-aerobic cultivation conditions. In some embodiments, the cultivation strategy entails nutrient limitation such as nitrogen, phosphate or oxygen limitation.

In some embodiments, a cell retention strategy using, for example, ceramic hollow fiber membranes can be employed to achieve and maintain a high cell density during either fed-batch or continuous fermentation.

In some embodiments, the principal carbon source fed to the fermentation in the synthesis of one or more C7 building blocks can derive from biological or non-biological feedstocks.

In some embodiments, the biological feedstock can be or can derive from, monosaccharides, disaccharides, lignocellulose, hemicellulose, cellulose, lignin, levulinic acid and formic acid, triglycerides, glycerol, fatty acids, agricultural waste, condensed distillers' solubles, or municipal waste.

The efficient catabolism of crude glycerol stemming from the production of biodiesel has been demonstrated in several microorganisms such as Escherichia coli, Cupriavidus necator, Pseudomonas oleavorans, Pseudomonas putida and Yarrowia hpolytica (Lee et al., Appl. Biochem. Biotechnol., 2012, 166:1801-1813; Yang et al., Biotechnology for Biofuels, 2012, 5:13; Meijnen et al., Appl. Microbiol. Biotechnol., 2011, 90:885-893).

The efficient catabolism of lignocellulosic-derived levulinic acid has been demonstrated in several organisms such as Cupriavidus necator and Pseudomonas putida in the synthesis of 3-hydroxyvalerate via the precursor propanoyl-CoA (Jaremko and Yu, 2011, supra; Martin and Prather, J. Biotechnol., 2009, 139:61-67).

The efficient catabolism of lignin-derived aromatic compounds such as benzoate analogues has been demonstrated in several microorganisms such as Pseudomonas putida, Cupriavidus necator (Bugg et al., Current Opinion in Biotechnology, 2011, 22, 394-400; Perez-Pantoja et al., FEMS Microbiol. Rev., 2008, 32, 736-794).

The efficient utilization of agricultural waste, such as olive mill waste water has been demonstrated in several microorganisms, including Yarrowia lipolytica (Papanikolaou et al., Bioresour. Technol., 2008, 99(7):2419-2428).

The efficient utilization of fermentable sugars such as monosaccharides and disaccharides derived from cellulosic, hemicellulosic, cane and beet molasses, cassava, corn and other agricultural sources has been demonstrated for several microorganism such as Escherichia coli, Corynebacterium glutamicum and Lactobacillus delbrueckii and Lactococcus lactis (see, e.g., Hermann et al, J. Biotechnol., 2003, 104:155-172; Wee et al., Food Technol. Biotechnol., 2006, 44(2):163-172; Ohashi et al., J. Bioscience and Bioengineering, 1999, 87(5):647-654).

The efficient utilization of furfural, derived from a variety of agricultural lignocellulosic sources, has been demonstrated for Cupriavidus necator (Li et al., Biodegradation, 2011, 22:1215-1225).

In some embodiments, the non-biological feedstock can be or can derive from natural gas, syngas, CO₂/H₂, methanol, ethanol, benzoate, non-volatile residue (NVR) or a caustic wash waste stream from cycloheptane oxidation processes, or terephthalic acid/isophthalic acid mixture waste streams.

The efficient catabolism of methanol has been demonstrated for the methylotrophic yeast Pichia pastoris.

The efficient catabolism of ethanol has been demonstrated for Clostridium kluyveri (Seedorf et al., Proc. Natl. Acad. Sci. USA, 2008, 105(6) 2128-2133).

The efficient catabolism of CO₂ and H₂, which may be derived from natural gas and other chemical and petrochemical sources, has been demonstrated for Cupriavidus necator (Prybylski et al., Energy, Sustainability and Society, 2012, 2:11).

The efficient catabolism of syngas has been demonstrated for numerous microorganisms, such as Clostridium ljungdahlii and Clostridium autoethanogenum (Kopke et al., Applied and Environmental Microbiology, 2011, 77(15):5467-5475).

The efficient catabolism of the non-volatile residue waste stream from cycloheptane processes has been demonstrated for numerous microorganisms, such as Delftia acidovorans and Cupriavidus necator (Ramsay et al., Applied and Environmental Microbiology, 1986, 52(1):152-156).

In some embodiments, the microorganism is a prokaryote. For example, the prokaryote can be a bacterium from the genus Escherichia such as Escherichia coli; from the genus Clostridia such as Clostridium ljungdahlii, Clostridium autoethanogenum or Clostridium kluyveri; from the genus Corynebacteria such as Corynebacterium glutamicum; from the genus Cupriavidus such as Cupriavidus necator or Cupriavidus metallidurans; from the genus Pseudomonas such as Pseudomonas fluorescens, Pseudomonas putida or Pseudomonas oleavorans; from the genus Delftia such as Delftia acidovorans; from the genus Bacillus such as Bacillus subtillis; from the genus Lactobacillus such as Lactobacillus delbrueckii; or from the genus Lactococcus such as Lactococcus lactis. Such prokaryotes also can be a source of genes to construct recombinant microorganisms described herein that are capable of producing one or more C7 building blocks.

In some embodiments, the microorganism is a eukaryote. For example, the eukaryote can be a filamentous fungus, e.g., one from the genus Aspergillus such as Aspergillus niger. Alternatively, the eukaryote can be a yeast, e.g., one from the genus Saccharomyces such as Saccharomyces cerevisiae; from the genus Pichia such as Pichia pastoris; or from the genus Yarrowia such as Yarrowia lipolytica; from the genus Issatchenkia such as Issathenkia orientalis; from the genus Debaryomyces such as Debaryomyces hansenii; from the genus Arxula such as Arxula adenoinivorans; or from the genus Kluyveromyces such as Kluyveromyces lactis. Such eukaryotes also can be a source of genes to construct recombinant microorganisms described herein that are capable of producing one or more C7 building blocks.

Metabolic Engineering

The present document provides methods involving less than all the steps described for all the above pathways. Such methods can involve, for example, one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve or more of such steps. Where less than all the steps are included in such a method, the first, and in some embodiments the only step can be any one of the steps listed.

Furthermore, recombinant microorganisms described herein can include any combination of the above enzymes such that one or more of the steps, e.g., one, two, three, four, five, six, seven, eight, nine, ten, or more of such steps, can be performed within a recombinant microorganism. This document provides microorganism cells of any of the genera and species listed and genetically engineered to express one or more (e.g., two, three, four, five, six, seven, eight, nine, 10, 11, 12 or more) recombinant forms of any of the enzymes recited in the document. Thus, for example, the microorganism cells can contain exogenous nucleic acids encoding enzymes catalyzing one or more of the steps of any of the pathways described herein.

In addition, this document recognizes that where enzymes have been described as accepting CoA-activated substrates, analogous enzyme activities associated with [acp]-bound substrates exist that are not necessarily in the same enzyme class.

Also, this document recognizes that where enzymes have been described accepting (R)-enantiomers of substrate, analogous enzyme activities associated with (S)-enantiomer substrates exist that are not necessarily in the same enzyme class.

This document also recognizes that where an enzyme is shown to accept a particular co-factor, such as NADPH, or co-substrate, such as acetyl-CoA, many enzymes are promiscuous in terms of accepting a number of different co-factors or co-substrates in catalyzing a particular enzyme activity. Also, this document recognizes that where enzymes have high specificity for e.g., a particular co-factor such as NADH, an enzyme with similar or identical activity that has high specificity for the co-factor NADPH may be in a different enzyme class.

In some embodiments, the enzymes in the pathways outlined herein are the result of enzyme engineering via non-direct or rational enzyme design approaches with aims of improving activity, improving specificity, reducing feedback inhibition, reducing repression, improving enzyme solubility, changing stereo-specificity, or changing co-factor specificity.

In some embodiments, the enzymes in the pathways outlined here can be gene dosed, i.e., overexpressed, into the resulting genetically modified organism via episomal or chromosomal integration approaches.

In some embodiments, genome-scale system biology techniques such as Flux Balance Analysis can be utilized to devise genome scale attenuation or knockout strategies for directing carbon flux to a C7 building block.

Attenuation strategies include, but are not limited to; the use of transposons, homologous recombination (double cross-over approach), mutagenesis, enzyme inhibitors and RNAi interference.

In some embodiments, fluxomic, metabolomic and transcriptomal data can be utilized to inform or support genome-scale system biology techniques, thereby devising genome scale attenuation or knockout strategies in directing carbon flux to a C7 building block.

In some embodiments, the microorganism's tolerance to high concentrations of a C7 building block can be improved through continuous cultivation in a selective environment.

In some embodiments, the microorganism's endogenous biochemical network can be attenuated or augmented to (1) ensure the intracellular availability of acetyl-CoA and β-alanine, (2) create an NADH or NADPH imbalance that may only be balanced via the formation of one or more C7 building blocks, (3) prevent degradation of central metabolites, central precursors leading to and including one or more C7 building blocks and/or (4) ensure efficient efflux from the cell.

In some embodiments requiring intracellular availability of acetyl-CoA for C7 building block synthesis, endogenous enzymes catalyzing the hydrolysis of acetyl-CoA such as short-chain length thioesterases can be attenuated in the microorganism.

In some embodiments requiring the intracellular availability of acetyl-CoA for C7 building block synthesis, an endogenous phosphotransacetylase generating acetate such as pta can be attenuated (Shen et al., Appl. Environ. Microbiol., 2011, 77(9):2905-2915).

In some embodiments requiring the intracellular availability of acetyl-CoA for C7 building block synthesis, an endogenous gene in an acetate synthesis pathway encoding an acetate kinase, such as ack, can be attenuated.

In some embodiments requiring the intracellular availability of acetyl-CoA and NADH for C7 building block synthesis, an endogenous gene encoding an enzyme that catalyzes the degradation of pyruvate to lactate such as lactate dehydrogenase encoded by ldhA can be attenuated (Shen et al., 2011, supra).

In some embodiments, enzymes that catalyze anapleurotic reactions such as PEP carboxylase and/or pyruvate carboxylase can be overexpressed in the microorganism.

In some embodiments requiring the intracellular availability of acetyl-CoA and NADH for C7 building block synthesis, endogenous genes encoding enzymes, such as menaquinol-fumarate oxidoreductase, that catalyze the degradation of phosphoenolpyruvate to succinate such as frdBC can be attenuated (see, e.g., Shen et al., 2011, supra).

In some embodiments requiring the intracellular availability of acetyl-CoA and NADH for C7 building block synthesis, an endogenous gene encoding an enzyme that catalyzes the degradation of acetyl-CoA to ethanol such as the alcohol dehydrogenase encoded by adhE can be attenuated (Shen et al., 2011, supra).

In some embodiments, where pathways require excess NADH co-factor for C7 building block synthesis, a recombinant formate dehydrogenase gene can be overexpressed in the microorganism (Shen et al., 2011, supra).

In some embodiments, where pathways require excess NADH co-factor for C7 building block synthesis, a recombinant NADH-consuming transhydrogenase can be attenuated.

In some embodiments, an endogenous gene encoding an enzyme that catalyzes the degradation of pyruvate to ethanol such as pyruvate decarboxylase can be attenuated.

In some embodiments requiring the intracellular availability of acetyl-CoA for C7 building block synthesis, a recombinant acetyl-CoA synthetase such as the gene product of acs can be overexpressed in the microorganism (Satoh et al., J. Bioscience and Bioengineering, 2003, 95(4):335-341).

In some embodiments, carbon flux can be directed into the pentose phosphate cycle to increase the supply of NADPH by attenuating an endogenous glucose-6-phosphate isomerase (EC 5.3.1.9).

In some embodiments, carbon flux can be redirected into the pentose phosphate cycle to increase the supply of NADPH by overexpression a 6-phosphogluconate dehydrogenase and/or a transketolase (Lee et al., 2003, Biotechnology Progress, 19(5), 1444-1449).

In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a gene such as UdhA encoding a puridine nucleotide transhydrogenase can be overexpressed in the microorganisms (Brigham et al., Advanced Biofuels and Bioproducts, 2012, Chapter 39, 1065-1090).

In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 Building Block, a recombinant glyceraldehyde-3-phosphate-dehydrogenase gene such as GapN can be overexpressed in the microorganisms (Brigham et al., 2012, supra).

In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a recombinant malic enzyme gene such as maeA or maeB can be overexpressed in the microorganisms (Brigham et al., 2012, supra).

In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a recombinant glucose-6-phosphate dehydrogenase gene such as zwf can be overexpressed in the microorganisms (Lim et al., J. Bioscience and Bioengineering, 2002, 93(6), 543-549).

In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a recombinant fructose 1,6 diphosphatase gene such as fbp can be overexpressed in the microorganisms (Becker et al., J. Biotechnol., 2007, 132:99-109).

In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, endogenous triose phosphate isomerase (EC 5.3.1.1) can be attenuated.

In some embodiments, where pathways require excess NADPH co-factor in the synthesis of a C7 building block, a recombinant glucose dehydrogenase such as the gene product of gdh can be overexpressed in the microorganism (Satoh et al., J. Bioscience and Bioengineering, 2003, 95(4):335-341).

In some embodiments, endogenous enzymes facilitating the conversion of NADPH to NADH can be attenuated, such as the NADH generation cycle that may be generated via inter-conversion of glutamate dehydrogenases classified under EC 1.4.1.2 (NADH-specific) and EC 1.4.1.4 (NADPH-specific).

In some embodiments, an endogenous glutamate dehydrogenase (EC 1.4.1.3) that utilizes both NADH and NADPH as co-factors can be attenuated.

In some embodiments, a membrane-bound cytochrome P450 such as CYP4F3B can be solubilized by only expressing the cytosolic domain and not the N-terminal region that anchors the P450 to the endoplasmic reticulum (Scheller et al., J. Biol. Chem., 1994, 269(17): 12779-12783).

In some embodiments, an enoyl-CoA reductase can be solubilized via expression as a fusion protein with a small soluble protein, for example, the maltose binding protein (Gloerich et al., FEBS Letters, 2006, 580, 2092-2096).

In some embodiments using microorganisms that naturally accumulate polyhydroxyalkanoates, the endogenous polymer synthase enzymes can be attenuated in the microorganism strain.

In some embodiments, a L-alanine dehydrogenase can be overexpressed in the microorganism to regenerate L-alanine from pyruvate as an amino donor for co-transaminase reactions.

In some embodiments, a L-glutamate dehydrogenase, a L-glutamine synthetase, or a alpha-aminotransaminase can be overexpressed in the microorganism to regenerate L-glutamate from 2-oxoglutarate as an amino donor for ω-transaminase reactions.

In some embodiments, enzymes such as a pimeloyl-CoA dehydrogenase classified under, EC 1.3.1.62; an acyl-CoA dehydrogenase classified, for example, under EC 1.3.8.7, EC 1.3.8.1, or EC 1.3.99.-; and/or a butyryl-CoA dehydrogenase classified, for example, under EC 1.3.8.6 that degrade central metabolites and central precursors leading to and including C7 building blocks can be attenuated.

In some embodiments, endogenous enzymes activating C7 building blocks via Coenzyme A esterification such as CoA-ligases (e.g., an adipyl-CoA synthetase) classified under, for example, EC 6.2.1.- can be attenuated.

In some embodiments, the efflux of a C7 building block across the cell membrane to the extracellular media can be enhanced or amplified by genetically engineering structural modifications to the cell membrane or increasing any associated transporter activity for a C7 building block.

The efflux of heptamethylenediamine can be enhanced or amplified by overexpressing broad substrate range multidrug transporters such as Blt from Bacillus subtilis (Woolridge et al., 1997, 1 Biol. Chem., 272(14):8864-8866); AcrB and AcrD from Escherichia coli (Elkins & Nikaido, 2002, J. Bacteriol., 184(23), 6490-6499), NorA from Staphylococcus aereus (Ng et al., 1994, Antimicrob Agents Chemother, 38(6), 1345-1355), or Bmr from Bacillus subtilis (Neyfakh, 1992, Antimicrob Agents Chemother, 36(2), 484-485).

The efflux of 7-aminoheptanoate and heptamethylenediamine can be enhanced or amplified by overexpressing the solute transporters such as the lysE transporter from Corynebacterium glutamicum (Bellmann et al., 2001, Microbiology, 147, 1765-1774).

The efflux of pimelic acid can be enhanced or amplified by overexpressing a dicarboxylate transporter such as the SucE transporter from Corynebacterium glutamicum (Huhn et al., Appl. Microbiol. & Biotech., 89(2), 327-335).

Producing C7 Building Blocks Using a Recombinant Microorganism

Typically, one or more C7 building blocks can be produced by providing a microorganism and culturing the provided microorganism with a culture medium containing a suitable carbon source as described above. In general, the culture media and/or culture conditions can be such that the microorganisms grow to an adequate density and produce a C7 building block efficiently. For large-scale production processes, any method can be used such as those described elsewhere (Manual of Industrial Microbiology and Biotechnology, 2^(nd) Edition, Editors: A. L. Demain and J. E. Davies, ASM Press; and Principles of Fermentation Technology, P. F. Stanbury and A. Whitaker, Pergamon). Briefly, a large tank (e.g., a 100 gallon, 200 gallon, 500 gallon, or more tank) containing an appropriate culture medium is inoculated with a particular microorganism. After inoculation, the microorganism is incubated to allow biomass to be produced. Once a desired biomass is reached, the broth containing the microorganisms can be transferred to a second tank. This second tank can be any size. For example, the second tank can be larger, smaller, or the same size as the first tank. Typically, the second tank is larger than the first such that additional culture medium can be added to the broth from the first tank. In addition, the culture medium within this second tank can be the same as, or different from, that used in the first tank.

Once transferred, the microorganisms can be incubated to allow for the production of a C7 building block. Once produced, any method can be used to isolate C7 building blocks. For example, C7 building blocks can be recovered selectively from the fermentation broth via adsorption processes. In the case of pimelic acid and 7-aminoheptanoic acid, the resulting eluate can be further concentrated via evaporation, crystallized via evaporative and/or cooling crystallization, and the crystals recovered via centrifugation. In the case of heptamethylenediamine and 1,7-heptanediol, distillation may be employed to achieve the desired product purity.

The invention will be further described in the following examples, which do not limit the scope of the invention described in the claims.

EXAMPLES Example 1

Enzyme Activity of ω-transaminase Using Pimelate Semialdehyde as Substrate and Forming 7-aminoheptanoate

A nucleotide sequence encoding a N-terminal His-tag was added to the nucleic acid sequences from Chromobacterium violaceum, Pseudomonas syringae, Rhodobacter sphaeroides, and Vibrio fluvialis encoding the ω-transaminases of SEQ ID NOs: 7, 9, 10 and 12, respectively (see FIG. 7D and FIG. 7E) such that N-terminal His-tagged co-transaminases could be produced. Each of the resulting modified genes was cloned into a pET21a expression vector under control of the T7 promoter and each expression vector was transformed into a BL21[DE3] E. coli strain. The resulting recombinant E. coli strains were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 16° C. using 1 mM IPTG.

The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation and the cell free extract was used immediately in enzyme activity assays.

Enzyme activity assays in the reverse direction (i.e., 7-aminoheptanoate to pimelate semialdehyde) were performed in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM 7-aminoheptanoate, 10 mM pyruvate and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding cell free extract of the ω-transaminase gene product or the empty vector control to the assay buffer containing the 7-aminoheptanoate and incubated at 25° C. for 4 h, with shaking at 250 rpm. The formation of L-alanine from pyruvate was quantified via RP-HPLC.

Each enzyme only control without 7-aminoheptanoate demonstrated low base line conversion of pyruvate to L-alanine. See FIG. 13. The gene product of SEQ ID NO 7, SEQ ID NO 9, SEQ ID NO 10 and SEQ ID NO 12 accepted 7-aminoheptanote as substrate as confirmed against the empty vector control. See FIG. 14.

Enzyme activity in the forward direction (i.e., pimelate semialdehyde to 7-aminoheptanoate) was confirmed for the transaminases of SEQ ID NO 9, SEQ ID NO 10 and SEQ ID NO 12. Enzyme activity assays were performed in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM pimelate semialdehyde, 10 mM L-alanine and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding a cell free extract of the ω-transaminase gene product or the empty vector control to the assay buffer containing the pimelate semialdehyde and incubated at 25° C. for 4 h, with shaking at 250 rpm. The formation of pyruvate was quantified via RP-HPLC.

The gene product of SEQ ID NO 9, SEQ ID NO 10 and SEQ ID NO 12 accepted pimelate semialdehyde as substrate as confirmed against the empty vector control. See FIG. 15. The reversibility of the ω-transaminase activity was confirmed, demonstrating that the ω-transaminases of SEQ ID NO: 7, SEQ ID NO: 9, SEQ ID NO: 10, and SEQ ID NO: 12 accepted pimelate semialdehyde as substrate and synthesized 7-aminoheptanoate as a reaction product.

Example 2

Enzyme Activity of Carboxylate Reductase Using Pimelate as Substrate and Forming Pimelate Semialdehyde

A nucleotide sequence encoding a HIS-tag was added to the nucleic acid sequences from Segniliparus rugosus and Segniliparus rotundus that encode the carboxylate reductases of SEQ ID NOs: 4 (EFV11917.1) and 6 (ADG98140.1), respectively (see FIG. 7B and FIG. 7C), such that N-terminal HIS tagged carboxylate reductases could be produced. Each of the modified genes was cloned into a pET Duet expression vector along with a sfp gene encoding a HIS-tagged phosphopantetheine transferase from Bacillus subtilis, both under the T7 promoter. Each expression vector was transformed into a BL21[DE3] E. coli strain and the resulting recombinant E. coli strains were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 37° C. using an auto-induction media.

The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication, and the cell debris was separated from the supernatant via centrifugation. The carboxylate reductases and phosphopantetheine transferases were purified from the supernatant using Ni-affinity chromatography, diluted 10-fold into 50 mM HEPES buffer (pH=7.5), and concentrated via ultrafiltration.

Enzyme activity assays (i.e., from pimelate to pimelate semialdehyde) were performed in triplicate in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 2 mM pimelate, 10 mM MgCl₂, 1 mM ATP and 1 mM NADPH. Each enzyme activity assay reaction was initiated by adding purified carboxylate reductase and phosphopantetheine transferase gene products or the empty vector control to the assay buffer containing the pimelate and then incubated at room temperature for 20 min. The consumption of NADPH was monitored by absorbance at 340 nm. Each enzyme only control without pimelate demonstrated low base line consumption of NADPH. See bars for EFV11917.1 and ADG98140.1 in FIG. 8.

The gene products of SEQ ID NO: 4 (EFV11917.1) and SEQ ID NO: 6 (ADG98140.1), enhanced by the gene product of sfp, accepted pimelate as substrate, as confirmed against the empty vector control (see FIG. 9), and synthesized pimelate semialdehyde.

Example 3

Enzyme Activity of Carboxylate Reductase Using 7-hydroxyheptanoate as Substrate and Forming 7-hydroxyheptanal

A nucleotide sequence encoding a His-tag was added to the nucleic acids from Mycobacterium marinum, Mycobacterium smegmatis, Segniliparus rugosus, Mycobacterium smegmatis, Mycobacterium massiliense, and Mycobacterium smegmatis that encode the carboxylate reductases of SEQ ID NOs: 2-6 and 15, respectively (GenBank Accession Nos. ACC40567.1, ABK71854.1, EFV11917.1, EIV11143.1, ADG98140.1, and ABK75684.1, respectively) (see FIG. 7A-C and FIG. 7E) such that N-terminal HIS tagged carboxylate reductases could be produced. Each of the modified genes was cloned into a pET Duet expression vector alongside a sfp gene encoding a His-tagged phosphopantetheine transferase from Bacillus subtilis, both under control of the T7 promoter. Each expression vector was transformed into a BL21[DE3] E. coli strain along with the expression vectors from Example 3. Each resulting recombinant E. coli strain was cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 37° C. using an auto-induction media.

The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation. The carboxylate reductases and phosphopantetheine transferase were purified from the supernatant using Ni-affinity chromatography, diluted 10-fold into 50 mM HEPES buffer (pH=7.5) and concentrated via ultrafiltration.

Enzyme activity (i.e., 7-hydroxyheptanoate to 7-hydroxyheptanal) assays were performed in triplicate in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 2 mM 7-hydroxyheptanal, 10 mM MgCl₂, 1 mM ATP, and 1 mM NADPH. Each enzyme activity assay reaction was initiated by adding purified carboxylate reductase and phosphopantetheine transferase or the empty vector control to the assay buffer containing the 7-hydroxyheptanoate and then incubated at room temperature for 20 min. The consumption of NADPH was monitored by absorbance at 340 nm. Each enzyme only control without 7-hydroxyheptanoate demonstrated low base line consumption of NADPH. See FIG. 8.

The gene products of SEQ ID NO 2-6 and 15, enhanced by the gene product of sfp, accepted 7-hydroxyheptanoate as substrate as confirmed against the empty vector control (see FIG. 10), and synthesized 7-hydroxyheptanal.

Example 4

Enzyme Activity of ω-transaminase for 7-aminoheptanol, Forming 7-oxoheptanol

A nucleotide sequence encoding an N-terminal His-tag was added to the Chromobacterium violaceum, Pseudomonas syringae and Rhodobacter sphaeroides nucleic acids encoding the ω-transaminases of SEQ ID NOs: 7, 9 and 10, respectively (see FIG. 7D) such that N-terminal HIS tagged ω-transaminases could be produced. The modified genes were cloned into a pET21a expression vector under the T7 promoter. Each expression vector was transformed into a BL21[DE3] E. coli strain. Each resulting recombinant E. coli strain were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 16° C. using 1 mM IPTG.

The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation and the cell free extract was used immediately in enzyme activity assays.

Enzyme activity assays in the reverse direction (i.e., 7-aminoheptanol to 7-oxoheptanol) were performed in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM 7-aminoheptanol, 10 mM pyruvate, and 100 pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding cell free extract of the ω-transaminase gene product or the empty vector control to the assay buffer containing the 7-aminoheptanol and then incubated at 25° C. for 4 h, with shaking at 250 rpm. The formation of L-alanine was quantified via RP-HPLC.

Each enzyme only control without 7-aminoheptanol had low base line conversion of pyruvate to L-alanine. See FIG. 13.

The gene products of SEQ ID NOs: 7, 9 & 10 accepted 7-aminoheptanol as substrate as confirmed against the empty vector control (see FIG. 18) and synthesized 7-oxoheptanol as reaction product. Given the reversibility of the ω-transaminase activity (see Example 1), it can be concluded that the gene products of SEQ ID Nos: 7, 9 & 10 accept 7-oxoheptanol as substrate and form 7-aminoheptanol.

Example 5

Enzyme Activity of ω-transaminase Using Heptamethylenediamine as Substrate and Forming 7-aminoheptanal

A nucleotide sequence encoding an N-terminal His-tag was added to the Chromobacterium violaceum, Pseudomonas aeruginosa, Pseudomonas syringae, Rhodobacter sphaeroides, Escherichia coli, and Vibrio fluvialis nucleic acids encoding the ω-transaminases of SEQ ID NOs: 7-12, respectively (see FIG. 7D and FIG. 7E) such that N-terminal HIS tagged ω-transaminases could be produced. The modified genes were cloned into a pET21a expression vector under the T7 promoter. Each expression vector was transformed into a BL21[DE3] E. coli strain. Each resulting recombinant E. coli strain were cultivated at 37° C. in a 250 mL shake flask culture containing 50 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 16° C. using 1 mM IPTG.

The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication. The cell debris was separated from the supernatant via centrifugation and the cell free extract was used immediately in enzyme activity assays.

Enzyme activity assays in the reverse direction (i.e., heptamethylenediamine to 7-aminoheptanal) were performed in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM heptamethylenediamine, 10 mM pyruvate, and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding cell free extract of the ω-transaminase gene product or the empty vector control to the assay buffer containing the heptamethylenediamine and then incubated at 25° C. for 4 h, with shaking at 250 rpm. The formation of L-alanine was quantified via RP-HPLC.

Each enzyme only control without heptamethylenediamine had low base line conversion of pyruvate to L-alanine. See FIG. 13.

The gene products of SEQ ID NOs: 7-12 accepted heptamethylenediamine as substrate as confirmed against the empty vector control (see FIG. 16) and synthesized 7-aminoheptanal as reaction product. Given the reversibility of the ω-transaminase activity (see Example 1), it can be concluded that the gene products of SEQ ID NOs: 7-12 accept 7-aminoheptanal as substrate and form heptamethylenediamine.

Example 6

Enzyme Activity of Carboxylate Reductase for N7-acetyl-7-aminoheptanoate, Forming N7-acetyl-7-aminoheptanal

The activity of each of the N-terminal His-tagged carboxylate reductases of SEQ ID NOs: 3, 5, and 6 (see Examples 2 and 3, and FIG. 7B and FIG. 7C) for converting N7-acetyl-7-aminoheptanoate to N7-acetyl-7-aminoheptanal was assayed in triplicate in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 2 mM N7-acetyl-7-aminoheptanoate, 10 mM MgCl₂, 1 mM ATP, and 1 mM NADPH. The assays were initiated by adding purified carboxylate reductase and phosphopantetheine transferase or the empty vector control to the assay buffer containing the N7-acetyl-7-aminoheptanoate then incubated at room temperature for 20 min. The consumption of NADPH was monitored by absorbance at 340 nm. Each enzyme only control without N7-acetyl-7-aminoheptanoate demonstrated low base line consumption of NADPH. See FIG. 8.

The gene products of SEQ ID NO 3, 5, and 6, enhanced by the gene product of sfp, accepted N7-acetyl-7-aminoheptanoate as substrate as confirmed against the empty vector control (see FIG. 11), and synthesized N7-acetyl-7-aminoheptanal.

Example 7

Enzyme Activity of ω-transaminase Using N7-acetyl-1,7-diaminoheptane, and Forming N7-acetyl-7-aminoheptanal

The activity of the N-terminal His-tagged ω-transaminases of SEQ ID NOs: 7-12 (see Example 5, and FIG. 7D and FIG. 7E) for converting N7-acetyl-1,7-diaminoheptane to N7-acetyl-7-aminoheptanal was assayed using a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 10 mM N7-acetyl-1,7-diaminoheptane, 10 mM pyruvate and 100 μM pyridoxyl 5′ phosphate. Each enzyme activity assay reaction was initiated by adding a cell free extract of the ω-transaminase or the empty vector control to the assay buffer containing the N7-acetyl-1,7-diaminoheptane then incubated at 25° C. for 4 h, with shaking at 250 rpm. The formation of L-alanine was quantified via RP-HPLC.

Each enzyme only control without N7-acetyl-1,7-diaminoheptane demonstrated low base line conversion of pyruvate to L-alanine. See FIG. 13.

The gene product of SEQ ID NOs: 7-12 accepted N7-acetyl-1,7-diaminoheptane as substrate as confirmed against the empty vector control (see FIG. 17) and synthesized N7-acetyl-7-aminoheptanal as reaction product.

Given the reversibility of the ω-transaminase activity (see Example 1), the gene products of SEQ ID NOs: 7-12 accept N7-acetyl-7-aminoheptanal as substrate forming N7-acetyl-1,7-diaminoheptane.

Example 8

Enzyme Activity of Carboxylate Reductase Using Pimelate Semialdehyde as Substrate and Forming Heptanedial

The N-terminal His-tagged carboxylate reductase of SEQ ID NO: 6 (see Example 3 and FIG. 7C) was assayed using pimelate semialdehyde as substrate. The enzyme activity assay was performed in triplicate in a buffer composed of a final concentration of 50 mM HEPES buffer (pH=7.5), 2 mM pimelate semialdehyde, 10 mM MgCl₂, 1 mM ATP and 1 mM NADPH. The enzyme activity assay reaction was initiated by adding purified carboxylate reductase and phosphopantetheine transferase or the empty vector control to the assay buffer containing the pimelate semialdehyde and then incubated at room temperature for 20 min. The consumption of NADPH was monitored by absorbance at 340 nm. The enzyme only control without pimelate semialdehyde demonstrated low base line consumption of NADPH. See FIG. 8.

The gene product of SEQ ID N: 6, enhanced by the gene product of sfp, accepted pimelate semialdehyde as substrate as confirmed against the empty vector control (see FIG. 12) and synthesized heptanedial.

Example 9

Enzyme Activity of 4-hydroxybuterate-CoA transferase Using 5-ethanamidopentanoic acid as Substrate and Forming 5-ethanamidopentanoyl-CoA and 7-ethanamido-3-oxoheptanoyl-CoA

A nucleotide sequence encoding a His-tag was added to the nucleic acid sequences from Cupriavidus necator, Clostridium propionicum, Clostridium aminobutyricum, Citrobacter sp. A1, Acetobacter aceti, and E. coli K12 encoding, in sequential order, the β-ketothiolase, priopionate CoA-transferase, 4-hydroxybuterate-CoA transferase. acetyl-CoA hydrolase, succinyl-CoA:acetate CoA-transferase, and thiolase of SEQ ID NOs: 16, 17, 18, 19, 20, and 21, respectively (see FIG. 7E and FIG. 7F) for production of His-tagged versions of each protein. Each of the resulting modified genes was cloned into a pET21a expression vector under control of the T7 promoter and each expression vector was transformed into a BL21[DE3] E. coli strain. The resulting recombinant E. coli strains were cultivated at 37° C. in a 500 mL shake flask culture containing 100 mL LB media and antibiotic selection pressure, with shaking at 230 rpm. Each culture was induced overnight at 20° C. using 0.5 mM IPTG.

The pellet from each induced shake flask culture was harvested via centrifugation. Each pellet was resuspended and lysed via sonication, and the cell debris was separated from the supernatant via centrifugation and passage through a 0.45 μm filter. Each of the His-tagged proteins was purified from the supernatant by Ni-affinity chromatography, diluted 10-fold into 50 mM HEPES buffer (pH=7.5), and concentrated by centrifugal filtration with a cut-off of 10 kD.

Enzyme assays were performed in two reactions for each of the substrates, N-acetyl-β-alanine (AC5) and 5-ethanamidopentanoic acid (AC7): reaction 1 and reaction 2 (see FIG. 19 for reaction schematic).

For reaction 1, each enzyme activity assay was performed in a buffer composed of a final concentration of 25 mM HEPES buffer (pH=7.5), 50 mM N-acetyl-β-alanine (AC5) or 50 mM 5-ethanamidopentanoic acid (AC7), and 2 mM acetyl CoA. Each enzyme activity assay was initiated by adding His-tag purified enzymes or the empty vector control to the assay buffer containing either the 50 mM N-acetyl-β-alanine or 5-ethanamidopentanoic acid and incubated at 37° C. for 2 h. The formation of 5-ethanamidopentanoyl-CoA and 7-ethanamido-3-oxoheptanoyl-CoA was monitored by LC-MS to identify products by expected masses at distinct retention times.

For reaction 2, each enzyme activity assay was performed in a buffer composed of a final concentration of 25 mM HEPES buffer (pH=7.5), 13 mM N-acetyl-β-alanyl-CoA (AC5-CoA) or 2.1 mM 5-ethanamidopentanoyl-CoA (AC7-CoA), and 5 mM acetyl CoA. Each enzyme activity assay was initiated by adding His-tag purified enzymes or the empty vector control to the assay buffer containing either the 50 mM N-acetyl-β-alanine or 5-ethanamidopentanoic acid (AC7-CoA) and incubated at 37° C. for 2 h. The formation of 7-ethanamido-3-oxoheptanoyl-CoA was monitored by LC-MS to identify products by expected masses at distinct retention times.

The 4-hydroxybuterate-CoA transferase gene product of SEQ ID NO: 18 accepted 5-ethanamidopentanoic acid and 5-ethanamidopentanoyl-CoA as substrate and formed 5-ethanamidopentanoyl-CoA and 7-ethanamido-3-oxoheptanoyl-CoA as products, which was confirmed against the empty vector control. See row for EC 2.8.3- in Table 1, and LC-MS mass peaks confirming product identity by expected mass in FIG. 21 (5-ethanamidopentanoyl-CoA: ESI MS expected [M+H]⁺=909.2017 and [M+2H]⁺²=445.1044; found 909.2017 and 445.1042) and FIG. 23 (7-ethanamido-3-oxoheptanoyl-CoA: ESI MS expected [M+H]⁺=951.2120 and [M+2H]⁺²=476.1097; found 951.2132 and 476.1091).

Table 1 below presents the results of the enzyme assays. The enzymes are listed by EC number, gene encoding the enzyme, and name. The enzyme assays were performed with acetyl-β-alanine (AC5) and 5-ethanamidopentanoic acid (AC7) substrates in a sequence of two reactions (see FIG. 19). Assays were monitored by LC-MS, and observed product (indicated by a check mark) and no product observed (indicated by x), are reported in Table 1 for the 4-hydroxybutyrate-CoA transferase.

AC5 AC7 Product Product Product Product Reac- Reac- Reac- Reac- E.C. Gene Name tion 1 tion 2 tion 1 tion 2 2.3.1.16/ Q0KBP1 BktB x x x x 2.3.1.9 2.8.3.8 Q9L3F7 237 x x x x 2.8.3- Q9RM86 244 x (?*) x (?*) ✓ ✓ 2.8.3.10 JIG510 337 x x x x 2.8.3.18 B3EY95 344 x x x x 2.3.1.174 P0C7L2 PaaJ x x x x *(?): Product (f) and (e) may be present but not clear.

Other Embodiments

It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. 

What is claimed is:
 1. A method of producing N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof, said method comprising enzymatically converting N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA or a salt thereof using a polypeptide having the activity of a β-ketoacyl synthase or a β-ketothiolase classified under EC. 2.3.1.- and/or a CoA transferase classified under EC 2.8.3.-, wherein said polypeptide having the activity of a β-ketothiolase has at least 90% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 1 or 13, said polypeptide having the activity of a β-ketoacyl synthase has at least 90% sequence identity to the amino acid sequence set forth in SEQ ID NO: 14, and said polypeptide having the activity of a CoA transferase has at least 90% sequence identity to the amino acid sequence set forth in SEQ ID NO:
 19. 2. The method of claim 1, wherein said polypeptide having the activity of a β-ketoacyl synthase is classified under EC 2.3.1.41, EC 2.3.1.179 or EC 2.3.1.180 and wherein said polypeptide having the activity of a β-ketothiolase is classified under EC 2.3.1.16 or EC 2.3.1.174.
 3. The method of claim 1, wherein said polypeptide having the activity of a β-ketothiolase has at least 90% sequence identity to the amino acid sequence set forth in SEQ ID NOs: 1 or 13 and is capable of converting N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA and said polypeptide having the activity of a β-ketoacyl synthase has at least 90% sequence identity to the amino acid sequence set forth in SEQID NO: 14 and is capable of converting N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA and said polypeptide having the activity of a CoA trans/erase has at least 90% sequence identity to the amino acid sequence set forth in SEQ ID NO: 19 and is capable of converting N-acetyl-3-aminopropanoyl-CoA to N-acetyl-5-amino-3-oxopentanoyl-CoA.
 4. The method of claim 1, further comprising enzymatically converting N-acetyl-5-amino-3-oxopentanoyl-CoA or the salt thereof to 7-aminoheptanoate using polypeptides having the enzymatic activities of a 3-hydroxyacyl-CoA dehydrogenase, an enoyl-CoA hydratase, a trans-2-enoyl-CoA reductase, a β-ketothiolase, a thioesterase or a CoA trans/erase and a deacetylase.
 5. The method of claim 4, said method further comprising enzymatically converting 7-aminoheptanoate to pimelic acid, 7-hydroxyheptanoate, heptamethylenediamine or 1,7-heptanediol or a corresponding salt thereof in one or more steps.
 6. The method of claim 5, wherein 7-aminoheptanoate is converted to pimelic acid using one or more polypeptides having the enzymatic activity of a ω-transaminase, a 7-oxoheptanoate dehydrogenase, a 6-oxohexanoate dehydrogenase, a 5-oxopentanoate dehydrogenase, or an aldehyde dehydrogenase.
 7. The method of claim 5, wherein 7-aminoheptanoate is converted to 7-hydroxyheptanoate using one or more polypeptides having the enzymatic activity of an alcohol dehydrogenase, a 6-hydroxyhexanoate dehydrogenase, a 5-hydroxypentanoate dehydrogenase, a 4-hydroxybutanoate dehydrogenase, and a ω-transaminase.
 8. The method of claim 5, wherein 7-aminoheptanoate is converted to heptamethylenediamine using polypeptides having the enzymatic activity of a carboxylate reductase and a ω-transaminase.
 9. The method of claim 5, wherein 7-aminoheptanoate is converted to heptamethylenediamine using polypeptides having the enzymatic activity of a carboxylate reductase, a ω-transaminase and an alcohol dehydrogenase.
 10. The method of claim 5, wherein 7-aminoheptanoate is converted to heptamethylenediamine using polypeptides having the enzymatic activity of an N-acetyltransferase, a carboxylate reductase, a ω-transaminase, and a deacetylase.
 11. The method of claim 5, wherein 7-aminoheptanoate is converted to heptamethylenediamine using polypeptides having the enzymatic activity of an alcohol dehydrogenase and a ω-transaminase.
 12. The method of claim 5, wherein 7-hydroxyheptanoate is converted to 1,7-heptanediol using a polypeptide having the activity of a carboxylate reductase and a polypeptide having the activity of an alcohol dehydrogenase.
 13. The method of claim 1, wherein said N-acetyl-3-aminopropanoyl-CoA is enzymatically produced from malonyl-CoA or L-aspartate.
 14. The method of claim 13, wherein said N-acetyl-3-aminopropanoyl-CoA is enzymatically produced from malonyl-CoA or L-aspartate using one or more polypeptides having the enzymatic activity of a malonyl-CoA-reductase, a β-alanine-pyruvate aminotransferase, an α-aspartate decarboxylase, an N-acetyl transferase, a CoA transferase and a CoA Ligase.
 15. The method of claim 1, wherein said method is performed in a recombinant microorganism.
 16. The method of claim 15, wherein said microorganism is subjected to a cultivation strategy under aerobic, anaerobic or, micro-aerobic cultivation conditions.
 17. The method of claim 15, wherein said microorganism is cultured under conditions of nutrient limitation.
 18. The method of claim 15, wherein the principal carbon source fed to the fermentation derives from a biological feedstock.
 19. The method of claim 15, wherein the principal carbon source fed to the fermentation derives from a non-biological feedstock.
 20. The method of claim 15, wherein the microorganism is a prokaryote.
 21. The method of claim 15, wherein the microorganism is a eukaryote.
 22. The method of claim 15, wherein the microorganism's tolerance to high concentrations of a C7 building block is improved relative to a wild type organism.
 23. The method of claim 15, wherein said microorganism comprises an attenuation to one or more of the following enzymes: polyhydroxyalkanoate synthase, an acetyl-CoA thioesterase, a phosphotransacetylase forming acetate, an acetate kinase, a lactate dehydrogenase, a menaquinol-fumarate oxidoreductase, an alcohol dehydrogenase forming ethanol, a triose phosphate isomerase, a pyruvate decarboxylase, a glucose-6-phosphate isomerase, NADH-consuming transhydrogenase, an NADH-specific glutamate dehydrogenase, a NADH/NADPH-utilizing glutamate dehydrogenase, a pimeloyl-CoA dehydrogenase; an acyl-CoA dehydrogenase accepting C7 building blocks and central precursors as substrates; a butaryl-CoA dehydrogenase; or an adipyl-CoA synthetase.
 24. The method of claim 15, wherein said microorganism overexpresses one or more genes encoding: an acetyl-CoA synthetase, a 6-phosphogluconate dehydrogenase; a transketolase; a puridine nucleotide transhydrogenase; a glyceraldehyde-3P-dehydrogenase; a malic enzyme; a glucose-6-phosphate dehydrogenase; a glucose dehydrogenase; a fructose 1,6 diphosphatase; a L-alanine dehydrogenase; a L-glutamate dehydrogenase; a formate dehydrogenase; a L-glutamine synthetase; a diamine transporter; a dicarboxylate transporter; and/or a multidrug transporter. 